- The school zone in front of your school has a posted speed limit of 25 mi/h, which is about 11 m/s. Let's
examine the stopping of a car in several different situations.
a. The crossing guard holds up her stop sign, and the driver is paying attention well. The car moves at a
constant velocity of 11 m/s for 2.3 seconds while the driver reacts, then slows down at a constant rate
of -4.5 m/s2. What is the stopping distance for the car in this situation?​

Answers

Answer 1

Answer:

s = 38.7 m

Explanation:

First we calculate the distance covered during uniform motion of reaction time.

s₁ = vt

where,

s₁ = distance covered during uniform motion = ?

v = uniform speed = 11 m/s

t = time = 2.3 s

Therefore,

s₁ = (11 m/s)(2.3 s)

s₁ = 25.3 m

Now, we calculate the distance covered during decelerated motion:

2as₂ = Vf² - Vi²

where,

a = deceleration = -4.5 m/s²

s₂ = distance covered during decelerated motion = ?

Vf = Final Velocity = 0 m/s

Vi = Initial Velocity = 11 m/s

Therefore,

2(-4.5 m/s²)s₂ = (0 m/s)² - (11 m/s)²

s₂ = (-121 m²/s²)/(-9 m/s²)

s₂ = 13.4 m

the total distance will be:

s = s₁ + s₂

s = 25.3 m + 13.4 m

s = 38.7 m


Related Questions

The density of water is 1.00 g/mL. This means if a rock has a density of 0.87 g/mL, it will ____in water.

a) float
b) sink

Answers

Answer:

Float

Explanation:

It is given that,

The density of water is 1 g/mL

The density of a rock is 0.87 g/mL

It can be seen that the density of water is more than that of rock. The density of an object is calculated from its mass and volume.

If the density of liquid in which it is placed, is more that that of the object, it will float at the top.

Hence, in this case the rock will float.

The friction of the water on a boat produces an acceleration of -10. m/s2. If the boat is traveling at 30. m/s and the motor is shut off, how long does it take the boat to slow down to 5.0 m/s?

Answers

Answer:2.5s

Explanation:

Someone please help me

Grandma has written up a new apple pie recipe with her crazy units again that you are trying to make. The recipe
calls for 6.25 x 10 cups of cinnamon How many teaspoons do you need?

Answers

Answer:

300x480 teaspoons

Explanation:

when converting cups to teaspoons just multiply by 48

Answer:

The answer should be 3tsp

Explanation:

3tsp

On what factors does the quantity of heat of an object depend?​

Answers

Explanation:

This quantity is known as the specific heat capacity (or simply, the specific heat), which is the heat capacity per unit mass of a material. Experiments show that the transferred heat depends on three factors: (1) The change in temperature, (2) the mass of the system, and (3) the substance and phase of the substance.

an object accelerated at 6.00m/s^2 starting at a velocity of 15.2m/s for 12.4 seconds. what is the objects final velocity?

Answers

The objects final velocity is 89.6m/s

What is the mass of a person that weighs 500 N on earth?

Answers

Answer:

M=51kg

Explanation:

Weight= Mass x Gravitational Acceleration

500N= M x 9.8 m/s^2

M= 51 kg

What is the IMA of the following pulley system?

Answers

The IMA of pulley system can be defined as the ratio of output force to input force.

And IMA stands for Ideal Mechanical advantage

Answer:

5

Explanation:

A ball is thrown straight up. If the launch velocity is 15 m/s, at what SPEED will the ball return to the thrower’s hand?


a) -15 m/s
b) -9.8 m/s
c) 15 m/s
d) 0 m/s

Answers

Answer:

Vf = 15 m/s

Explanation:

First we consider the upward motion of ball to find the height reached by the ball. Using 3rd equation of motion:

2gh = Vf² - Vi²

where,

g = acceleration due to gravity = -9.8 m/s² (negative sign for upward motion)

h = height =?

Vf = Final Velocity = 0 m/s (Since, ball momentarily stops at highest point)

Vi = Initial Velocity = 15 m/s

Therefore,

2(-9.8 m/s²)h = (0 m/s)² - (15 m/s)²

h = (-225 m²/s²)/(-19.6 m/s²)

h = 11.47 m

Now, we consider downward motion:

2gh = Vf² - Vi²

where,

g = acceleration due to gravity = 9.8 m/s²

h = height = 11.47 m

Vf = Final Velocity = ?

Vi = Initial Velocity = 0 m/s

Therefore,

2(9.8 m/s²)(11.47 m) = Vf² - (0 m/s)²

Vf = √(224.812 m²/s²)

Vf = 15 m/s

You drive 200 miles in 3 hours before stopping for lunch and gas. After lunch you
travel 250 miles in an hour and a half What was your average speed in mi/hr)
for the trip

Answers

Given :

You drive 200 miles in 3 hours before stopping for lunch and gas. After lunch you  travel 250 miles in an hour and a half.

To Find :

Average speed.

Solution :

We know, average speed is given by :

[tex]v=\dfrac{\text{Total distance covered}}{\text{Total time taken}}\\\\v=\dfrac{200+250}{3+1.5}\ miles/hr\\\\v=\dfrac{450}{4.5}\ miles/hr\\\\v=100\ miles/hr[/tex]

Therefore, average speed of the journey is 100 miles/hr.

Hence, this is the required solution.

The smallest units of life that make up all living things are Group of answer choices tissues organ system organs cells

Answers

Answer:

Cells is your answer

Explanation:

Cells are the basic unit of life

hope this helped you

please mark as the brainliest (ㆁωㆁ)

A forklift does 450 J of work to lift a 150 N hot tub. How high is the hot tub lifted? Round your answer to the nearest whole number

Answers

Answer:

3 m

Explanation:

[tex]work \: = force \times displacement \\ 450 = 150 \times displacement \\ displacement = 3m[/tex]

One way to decrease acceleration is to
a. increase mass
b. decrease mass
c. decrease force and mass equally
d. increase force more than mass

Answers

To decrease acceleration is to increase mass and to increase acceleration u have to decrease ur mass

A _________ reactive metal replaces a ____________ reactive metal in a chemical reaction. A. Less, more B. More, similar C. Similar, Less D. More, less

Answers

The answer is D. A more reactive metal replaces a less reactive metal in a chemical reaction.

Can some one help please i’m in danger !

Answers

Formula:

Distance = Speed × Time

Answer:Level 1:

The distance travelled during 5 hours = 0 × 5 = 0 km

Level 2:

The distance travelled during 5 hours = 50 × 5 = 250 km

Level 3:

The distance travelled during 5 hours = 60 × 5 = 300 km

Level 4:

The distance travelled during 5 hours = 60 × 4 = 240 km

How do you line up vectors so you can add them?

Answers

Answer:

The head-to-tail method of adding vectors involves drawing the first vector on a graph and then placing the tail of each subsequent vector at the head of the previous vector. The resultant vector is then drawn from the tail of the first vector to the head of the final vector.

Explanation:

two vectors, you place the tail of the second vector to the tip of the first vector while maintaining vector orientation. The resultant vector is a vector that begins at the tail of the first vector and points in a straight line to the tip of the second vector.

How many ways (directions) can an object move in 1 Dimension? Can it be still? Can it speed up or slow down?

Answers

Explanation:

Let's assume the 1D is along x - axis.

Then, the object can move in two directions, along +x axis or - x axis, depending upon reference point .

Yes, it can be still, speed up and slow down.

A little girl riding a train rolls a ball toward the back of the train at 1.25 m/s NE. The train is traveling at a velocity of 13.22 m/s SW. The little girl's brother runs from the back of the train, toward the rolling ball at a velocity of 1.45 m/s SW. Relative to the little girl's brother, what is the velocity of the rolling ball?

Answers

Answer:

Answer: 2.70m/s NE

Explanation:

Just did it.

The gravitational acceleration on Earth is 9.8 m/s2. What is the weight of a car on Earth (to the nearest whole number) if it has a mass of 1360 kg? 14 N 139 N 1333 N 13,328 N

Answers

Weight = (mass) x (gravitational acceleration where the mass is)

Weight = (1360 kg) x (9.8 m/s²)

Weight = 13,328  kg-m/s²

That's 13,328 Newtons

Given:-

Mass (m) of the car = 1360 kgAcceleration due to gravity (g) = 9.8 m/

To Find: Weight (W).

We know,

W = mg

where,

W = Weight,m = Mass &g = Acceleration due to gravity.

Thus,

W = (1360 kg)(9.8 m/s²)

→ W = 13,328 N (D)


1. How should Rick correct his technique?
2. Are these students behaving appropriately? If not, what should they
be doing differently?
the guy on the left is rick , the girl in the middle is sarah, and the guy on the right is Andrew.

Answers

Answer:

1) Rick should be taking and gathering the gas with his hand towards his face gently to get just a whiff.

2) These students are doing the complete opposite of what should properly be done. Andrew shouldn't be drinking any chemicals that don't belong in his body. Sarah shouldn't be throwing whatever chemicals into a mixture, this can cause a lot of possible danger. Rick shouldn't be directly smelling the gas which can also be harmful. Rick needs to be wearing gloves and smell the gas in a proper way. Sarah should wear goggles and pay attention to what she is mixing. Andrew should be wearing gloves and goggles and shouldn't be drinking the chemical.

WHO IS GOOD AT PHYSICAL SCIENCE PLS COME HERE AND HELP ME OUT!!!!

Answers

me i’m very good!! just lmk a question

Which property of an object is the result of gravity?
O A. Weight
B. Mass
O C. Velocity
OD. Volume

Answers

Answer:

it's (A) weight I think

Answer:

A. Weight

Explanation: Weight is defined as the amount of force placed on an object from gravity which means it is directly reliant on the force of gravity while the other choices are not. Neither Mass, volume, or velocity is impacted by gravity as much as weight, velocity is the direction of speed, mass is the resistance that a body of matter offers to a change in its speed or position upon the application of a force, and volume is the amount of space an object takes. As you can see none of these componant have gravity as a determining factor other than weight since weight is determined by the gravity which is why the weight of an object can vary if your on earth or on the moon since the gravity is different.

What is 50,000 in exponential notation?

Answers

Answer:

To write 50000 in scientific notation, we will have to move the decimal point four points to left, which literally means dividing by 104 . Hence in scientific notation 50000=5×104 (note that as we have moved decimal four points to left and thus divided by 104 , we are multiplying by 104 to compensate.

Explanation:

Cuts are ________, meaning an injury to the skin and the soft tissue underneath it.
A. contusions
B. lacerations
C. abrasions
D. bruises

Answers

Answer:

lacerations

Explanation:

Answer:

B. lacerations

Explanation:

A P E X!

A car was traveling at a velocity of 8 m/s and then accelerated at a rate of 5 m/sr^2, reaching a velocity of 85 m/s. How far did the car travel at this acceleration rate?

Answers

Answer:

716.1 m

Explanation:

A car was travelling at a velocity of 8m/s

It accelerated at 5m/s^2

It finally reached a velocity of 85m/s

The distance can be calculated by applying the fourth equation of motion

V^2= U^2 +2as

V= 85m/s

U= 8m/s

a= 5m/s^2

85^2= 8^2 + 2(5)(s)

7225= 64 + 10s

7225-64= 10s

7161=10s

s= 7161/10

= 716.1 m

Hence the car travelled at a distance of 716.1 m

1. Why are the speed values in the data table called "average" instead of "instantaneous"?

Answers

Answer: Why are the speed values in Table 1 called "average" instead of "instantaneous"? The speeds are called average because they are a calculation of a course of distance divided by aduration of time. ... The average speed reduces.

HOPE IT HELPS:) HAVE A NICE DAY

Answer:

The speeds are called average because they are a calculation of a course of distance divided by a duration of time.

Explanation: Instantaneous speed is when the speed is instant for instance when driving a car and if you would want to check how fast that you are moving you would instantly look at the speedometer that is what we call instantaneous speed

List the planets that have MORE THAN 3 moons.

Answers

Answer:

jupiter they have 79 moons,saturn has 62,uranus has 27,neptune has 14,pluto has 5,

Explanation:

Steve is recording the temperature of an object on Celsius and Fahrenheit scales. Relationship between the two scales is given by F = 1.8 ⋅ C. Steve will plot the Celsius readings along the y-axis and the Fahrenheit readings along the x-axis. (5 points) True False

Answers

Answer:

False

Explanation:

since the Farenheit depends on the amount of Celsius times (*) 1.8 (F= 1.8 * C),

then we can deduce that Farenheit is the dependent variable while celsius is independent. after this, remember that the independent variable is the X value and the dependent variable is the Y value.

can someone explain what is electric energy???​

Answers

The energy produce by electricity is known as electric energy.

Answer:

Electrical energy is energy derived from electrical potential energy or kinetic energy

Explanation:

when used loosely ,electrical energy refers to energy that has been converted from potential energy.

A block has two forces on it. One force is 15 N going north and the other is 22 N going east. What is the overall force pushing on the block with magnitude and direction?

Answers

Answer:

The overall force pushing on the block is 26.63 N in the direction of N 34° E

Explanation:

Given;

force going north, F₁ = 15 N

force going east, F₂ = 22 N

The resultant of the two forces is the hypotenuse side of the right angled triangle formed by the two forces.

Let the magnitude of the resultant force = F

F² = F₁² + F₂²

F = √(F₁² + F₂²)

F = √(15² + 22²)

F = 26.63 N

The direction of the force is the angle between the resultant force and the horizontal force.

tan θ = 15 / 22

tan θ = 0.6818

θ = tan⁻¹ ( 0.6818)

θ = 34°

Therefore, the overall force pushing on the block is 26.63 N in the direction of N 34° E

hey can anyone pls help me out in dis!

Answers

Answer:

A. Liquid becomes a gas.

Answer:

A

Explanation:

Water changes to liquid because hydrogen bonds are constantly formed and broken as the water molecules slide past each other. The breaking of these bonds is caused by the motion (kinetic energy) of the water molecules due to the heat contained in the system.

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