Q: A postal worker walks 161 m due east from his truck, then turns around and walks 194 m due west. What is the worker's displacement relative to his truck?

$$33\ \mathrm{m},\ \text{due west}$$

Q: A landing airplane makes contact with the runway with a speed of $$75.0\ \mathrm{m/s}$$ and moves toward the south. After $$18.5$$ seconds, the airplane comes to rest. What is the average acceleration of the airplane during the landing?

$$-4.05\ \mathrm{m/s^2$},\ \text{south}$$

Q: A car travels due east at $$22\ \mathrm{m/s}. It $$makes a turn due south and continues to travel at $$22\ \mathrm{m/s}. $$What is the change in velocity of the car?

$$31\ \mathrm{m/s},\ 45^\circ\ \text{south of west}$$

Q: At time $$t=0\ \mathrm{s}$$, a puck is sliding on a horizontal table with a velocity $$3.60\ \mathrm{m/s}$$, $$35.0^\circ$$ above the x-axis. As the puck slides, a constant acceleration acts on it that has the following components: $$a_x = -0.360\ \mathrm{m/s^2$}$$ and $$a_y = -0.980\ \mathrm{m/s^2$}. $$What is the velocity of the puck at time $$t = 1.50\ \mathrm{s}$$?

$$2.48\ \mathrm{m/s},\ 13.9^\circ\ \text{above the x-axis}$$

Question 1

A postal worker walks 161 m due east from his truck, then turns around and walks 194 m due west. What is the worker's displacement relative to his truck?

Accepted Answer

$$33\ \mathrm{m},\ 	ext{due west}$$

Question 2

During the first 18 minutes of a 1.0-hour trip, a car has an average speed of 11 m/s. What must be the average speed of the car during the last 42 minutes of the trip if the car is to have an average speed of 21 m/s for the entire trip?

Accepted Answer

$$27\ \mathrm{m/s}$$

Question 3

Which of the following situations describes a car with a westward acceleration?

Accepted Answer

The car travels eastward and slows down.

Question 4

A landing airplane makes contact with the runway with a speed of $$75.0\ \mathrm{m/s}$$ and moves toward the south. After $$18.5$$ seconds, the airplane comes to rest. What is the average acceleration of the airplane during the landing?

Accepted Answer

$$-4.05\ \mathrm{m/s^2$},\ 	ext{south}$$

Question 5

A car travels due east at $$22\ \mathrm{m/s}. It $$makes a turn due south and continues to travel at $$22\ \mathrm{m/s}. $$What is the change in velocity of the car?

Accepted Answer

$$31\ \mathrm{m/s},\ 45^\circ\ 	ext{south of west}$$

Question 6

At time $$t=0\ \mathrm{s}$$, a puck is sliding on a horizontal table with a velocity $$3.60\ \mathrm{m/s}$$, $$35.0^\circ$$ above the x-axis. As the puck slides, a constant acceleration acts on it that has the following components: $$a_x = -0.360\ \mathrm{m/s^2$}$$ and $$a_y = -0.980\ \mathrm{m/s^2$}. $$What is the velocity of the puck at time $$t = 1.50\ \mathrm{s}$$?

Accepted Answer

$$2.48\ \mathrm{m/s},\ 13.9^\circ\ 	ext{above the x-axis}$$

Question 7

How long would it take an object, falling from rest, to fall $$16\ \mathrm{m} on a $$planet where $$g = 8.0\ \mathrm{m/s^2$}$$?

Accepted Answer

$$2.0\ \mathrm{s}$$

Question 8

Neglecting air resistance, what maximum height will be reached by an arrow launched straight upward with an initial speed of $$35\ \mathrm{m/s}$$?

Accepted Answer

$$63\ \mathrm{m}$$

Question 9

A quarterback throws a pass at an angle of $$35^\circ$$ above the horizontal with an initial speed of $$25\ \mathrm{m/s}. $$The ball is caught by the receiver $$2.55$$ seconds later. Determine the distance the ball was thrown.

Accepted Answer

$$52\ \mathrm{m}$$

Question 10

If the speed of the second ball fired is twice the speed of the first ball fired, how is the horizontal range $$R$$ affected (neglecting air resistance)?

Accepted Answer

The range of the second ball will be four times as large as that of the first ball.

Question 11

A rock is kicked horizontally at a speed of $$16\ \mathrm{m/s}$$ from the edge of a cliff. The rock strikes the ground $$65\ \mathrm{m}$$ from the foot of the cliff of height $$H. $$How long is the rock in the air?

Accepted Answer

$$4.0\ \mathrm{s}$$

Question 12

A net force of $$25\ \mathrm{N} is $$applied for $$5.7\ \mathrm{s} to a$$ $$12\ \mathrm{kg}$$ box initially at rest. What is the speed of the box at the end of the $$5.7\ \mathrm{s}$$ interval?

Accepted Answer

$$12\ \mathrm{m/s}$$

Question 13

What is the weight of a $$2.50\ \mathrm{kg}$$ bag of sand on the surface of the earth?

Accepted Answer

$$24.5\ \mathrm{N}$$

Question 14

A $$2.0\ \mathrm{N}$$ rock slides on a frictionless inclined plane. Which one of the following statements is true concerning the normal force that the plane exerts on the rock?

Accepted Answer

The normal force is less than $$2.0\ \mathrm{N}$$, but greater than zero newtons. It decreases as the angle of inclination, $$	heta$$, is increased.

Question 15

A muscle builder holds the ends of a massless rope. At the center of the rope, a $$7.9\ \mathrm{kg}$$ ball is hung as shown. What is the tension in the rope if the angle $$	heta in $$the drawing is $$6.0^\circ$$?

Accepted Answer

$$370\ \mathrm{N}$$

Question 16

What is the magnitude of the tension in the string holding a block of mass $$M on an $$inclined plane at angle $$	heta$$?

Accepted Answer

$$M g \sin 	heta$$

Question 17

A $$71\ \mathrm{kg}$$ man stands on a bathroom scale in an elevator. What does the scale read if the elevator is ascending with an acceleration of $$3.0\ \mathrm{m/s^2$}$$?

Accepted Answer

$$980\ \mathrm{N}$$

Question 18

A $$10\ \mathrm{kg}$$ block is pressed against a vertical wall by a $$100\ \mathrm{N}$$ horizontal force. Which statement is true, if the block is initially at rest?

Accepted Answer

The block will remain at rest because the coefficient of static friction is greater than the coefficient of kinetic friction.

Question 19

A $$5.9\ \mathrm{N}$$ force acts at $$43^\circ to $$the horizontal and a $$3.7\ \mathrm{N}$$ force acts horizontally on a $$4.5\ \mathrm{kg}$$ block resting on a frictionless surface. What is the magnitude of the horizontal acceleration of the block?

Accepted Answer

$$1.2\ \mathrm{m/s^2$}$$

Kinematics and Newtonian Mechanics: Study Guide

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