Question 1

A ball is thrown horizontally from the top of a 45.0 m tall building and lands 24.0 m from the base. What was the ball’s initial speed?

Accepted Answer

$$7.92\ \mathrm{m/s}$$

Question 2

Which of the following best describes the path of a projectile under the influence of gravity (neglecting air resistance)?

Accepted Answer

A parabola

Question 3

A tiger leaps horizontally from a 6.5 m high rock with a speed of $$3.5\ \mathrm{m/s}. $$How far from the base of the rock will she land? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$4.0\ \mathrm{m}$$

Question 4

A football is kicked at ground level with a speed of $$18.0\ \mathrm{m/s} at an $$angle of $$35.0^\circ to $$the horizontal. How long is the ball in the air before it lands? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$2.10\ \mathrm{s}$$

Question 5

For a projectile launched at an angle $$\$$theta_0$$ with initial speed v_0$, what is the formula for the range R$ (horizontal distance traveled) on level ground?

Accepted Answer

$$R = \dfrac{v_0$^2 \sin 2\$$theta_0$$}{g}$$

Question 6

A pilot flying horizontally at $$180\ \mathrm{km/h}$$ wants to drop supplies to victims on the ground $$160\ \mathrm{m}$$ below. How many seconds before the plane is directly overhead should the supplies be released? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$2.86\ \mathrm{s}$$

Question 7

Which of the following statements about projectile motion is correct?

Accepted Answer

The vertical acceleration is constant and equal to $$g.$$

Question 8

An athlete executes a long jump at a $$28.0^\circ$$ angle and travels $$7.80\ \mathrm{m}. $$What was the takeoff speed? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$8.60\ \mathrm{m/s}$$

Question 9

If the takeoff speed in the previous long jump problem is increased by $$5.0\%$$, how much longer would the jump be?

Accepted Answer

$$8.97\ \mathrm{m}$$

Question 10

A ball is thrown horizontally from a cliff and lands a certain distance away. If the height of the cliff is doubled, what happens to the horizontal distance (range), assuming the initial speed is unchanged?

Accepted Answer

It increases by a factor of $$\sqrt{2}.$$

Question 11

Which kinematic equation correctly describes the vertical position $$y of a $$projectile as a function of time $$t ($$assuming upward is positive and $$y_0 is $$the initial height)?

Accepted Answer

$$y = y_0$ + v_{y0} t - \dfrac{1}{2} g t^2$

Question 12

A projectile is launched at an angle $$\$$theta_0$$ with initial speed v_0$. What is the vertical component of its initial velocity?

Accepted Answer

$$v_0$$ \sin \$$theta_0$$

Question 13

A projectile is launched at $$20.0\ \mathrm{m/s} at an $$angle of $$45.0^\circ$$ above the horizontal. What is the maximum height it reaches? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$10.2\ \mathrm{m}$$

Question 14

Which of the following is true about the velocity of a projectile at the highest point of its trajectory?

Accepted Answer

The vertical component of velocity is zero.

Question 15

A ball is thrown horizontally from a building. Which of the following best describes its acceleration during flight (neglecting air resistance)?

Accepted Answer

Constant and downward, equal to $$g$$

Question 16

A projectile is launched horizontally from a height $$h$$ with speed $$v_0. $$What is the time it takes to hit the ground?

Accepted Answer

$$t = \sqrt{\dfrac{2h}{g}}$$

Question 17

A projectile is launched at $$v_0$$ and angle $$\$$theta_0$$. Which of the following would increase the range of the projectile, assuming all other factors remain constant?

Accepted Answer

Increasing the launch angle from $$30^\circ to$$ $$45^\circ$$

Question 18

A ball is thrown horizontally from a building and lands 30 m from the base. If the initial speed is doubled, how far from the base will it land (assuming the same height)?

Accepted Answer

60 m

Projectile Motion: Concepts and Problem Solving (Giancoli Physics, Chapter 3)

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