Question 1

A car is traveling at an initial speed $$V_0$$ and comes to a stop with constant deceleration $$a. $$Which equation gives the distance $$x$$ the car travels before stopping?

Accepted Answer

$$x = \frac{V_0$^2}{2a}$$

Question 2

A ball is thrown straight up with initial velocity $$V_0. $$What is the time it takes to reach its highest point?

Accepted Answer

$$t = \frac{V_0$}{g}$$

Question 3

A police officer is at rest when a speeder passes by at constant velocity $$V. $$The officer immediately accelerates from rest with constant acceleration $$a. $$How much time $$t$$ does it take for the officer to catch up to the speeder?

Accepted Answer

$$t = \frac{V}{a}$$

Question 4

Which of the following is the correct kinematic equation for position $$x as a $$function of time $$t$$ for constant acceleration $$a$$?

Accepted Answer

$$x = x_0$ + v_0$ t + \frac{1}{2} a t^2$

Question 5

A ball is thrown straight up and returns to the thrower's hand. Neglecting air resistance, what is the acceleration due to gravity at the highest point?

Accepted Answer

It is $$g$$ downward.

Question 6

A marble is launched horizontally from a table at the same instant a second marble is dropped from the same height. Which marble hits the ground first?

Accepted Answer

They both hit at the same time.

Question 7

A football is kicked at an angle $$	heta$$ with initial speed $$V_0$$ from a height $$h$$ above the ground. Which angle maximizes the horizontal distance traveled (range) if $$h=0$$?

Accepted Answer

$$	heta = 45^\circ$$

Question 8

A monkey drops from a tree at the same instant a tranquilizer dart is fired directly at it. Ignoring air resistance, where should the dart be aimed to hit the monkey?

Accepted Answer

Right at the monkey.

Question 9

A swimmer wants to cross a river of width $$D$$ with current speed $$v_r. $$The swimmer's speed in still water is $$v_s. $$What is the minimum time to cross the river?

Accepted Answer

$$t = \frac{D}{v_s}$$

Question 10

A person stands on a moving sidewalk traveling at $$2\ \mathrm{m/s} to $$the right. A dog runs toward the person at $$8\ \mathrm{m/s}$$ relative to the sidewalk, in the opposite direction. What is the speed of the dog relative to the ground?

Accepted Answer

$$6\ \mathrm{m/s}$$

Question 11

A ball is thrown upward with initial velocity $$V_0. $$What is its velocity when it returns to the thrower's hand (neglecting air resistance)?

Accepted Answer

$$-V_0$

Question 12

A projectile is launched at an angle $$	heta$$ with initial speed $$V_0. $$Which of the following statements is true about its horizontal and vertical motions (neglecting air resistance)?

Accepted Answer

The horizontal and vertical motions are independent.

Question 13

A train is moving at $$v_1$$ and applies brakes with constant deceleration $$a to $$avoid a collision with a stationary object $$d$$ meters ahead. What is the minimum deceleration required to stop just before the object?

Accepted Answer

$$a = \frac{v_1$^2}{2d}$$

Question 14

A person walks across a $$4\ \mathrm{m}$$ wide moving sidewalk at $$1\ \mathrm{m/s}$$ perpendicular to the sidewalk, which moves at $$2\ \mathrm{m/s}$$ relative to the ground. How far from the point directly across will the person be when reaching the other side?

Accepted Answer

$$8\ \mathrm{m}$$

Question 15

A ball is thrown upward from the edge of a building and another is thrown downward with the same speed. Neglecting air resistance, which ball has the greater speed when it hits the ground?

Accepted Answer

Both have the same speed.

Question 16

Which of the following equations is NOT a correct kinematic equation for constant acceleration?

Accepted Answer

$$x = x_0$ + at^2$

Question 17

A projectile is fired at an angle $$	heta$$ above the horizontal with speed $$V_0. $$What is the vertical component of its velocity at launch?

Accepted Answer

$$V_0$$ \sin 	heta$$

Question 18

A boat wants to cross a river directly from point A to point B, which are directly opposite each other. The river flows at $$v_r$$ and the boat's speed in still water is $$v_b. $$Under what condition is it possible for the boat to reach point B?

Accepted Answer

$$v_b \u003e v_r$$

Kinematics: One-Dimensional and Two-Dimensional Motion

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