Question 1

A ball is launched from the ground at an angle of $$35.0^\circ$$ above the horizontal with an initial speed of $$20.0\ \mathrm{m/s}. $$What is the $$y-$$component of the ball's velocity at $$t = 1.50\ \mathrm{s}$$? (Assume $$g = 9.81\ \mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$v_y = -3.22\ \mathrm{m/s}$$

Question 2

An eagle descends from a branch $$19.5\ \mathrm{m}$$ above the water, flying at a constant speed of $$3.10\ \mathrm{m/s} at$$ $$20.0^\circ$$ below the horizontal. How long does it take the eagle to reach the water?

Accepted Answer

$$t = 18.4\ \mathrm{s}$$

Question 3

A helicopter moves horizontally at $$11\ \mathrm{m/s}$$ and then accelerates vertically upward at $$0.96\ \mathrm{m/s^2$}. $$What is the helicopter's velocity vector at $$t = 5.3\ \mathrm{s} in $$unit vector notation?

Accepted Answer

$$\vec{v} = (11\ \mathrm{m/s})\hat{x} + (5.1\ \mathrm{m/s})\hat{y}$$

Question 4

Which of the following best describes the acceleration of a projectile in free fall (neglecting air resistance)?

Accepted Answer

$$a_x = 0$$, $$a_y = -g$$

Question 5

A projectile is launched from the origin with $$v_0 = 20.0$$\ \mathrm{m/s}$$ at 35.0$$^\circ$$ above the horizontal. What is the maximum height reached by the projectile?

Accepted Answer

$$6.74\ \mathrm{m}$$

Question 6

At what time does the projectile from the previous question reach its maximum height?

Accepted Answer

$$t = 1.17\ \mathrm{s}$$

Question 7

A helicopter starts at rest and accelerates upward at $$0.96\ \mathrm{m/s^2$}$$ while moving horizontally at $$11\ \mathrm{m/s}. $$How far has it traveled horizontally when it is $$18\ \mathrm{m}$$ above its starting point?

Accepted Answer

$$67\ \mathrm{m}$$

Question 8

A ball is thrown horizontally from a cliff with an initial speed $$v_0. $$Which of the following statements is true about its acceleration during flight (neglecting air resistance)?

Accepted Answer

The acceleration is constant and directed downward.

Question 9

A projectile is launched from the ground with an initial velocity $$v_0 at an $$angle $$	heta$$ above the horizontal. Which equation gives the $$x-$$position as a function of time?

Accepted Answer

$$x = x_0$ + v_{0x} t$$

Question 10

A projectile is launched from the origin with $$v_0 = 20.0$$\ \mathrm{m/s}$$ at 35.0$$^\circ$$ above the horizontal. What is the x$-component of its velocity at any time during flight (neglecting air resistance)?

Accepted Answer

$$v_x = 16.4\ \mathrm{m/s}$$

Question 11

A ball is thrown straight up with an initial velocity $$v_0. At $$the top of its path, which of the following is true?

Accepted Answer

The vertical velocity is zero, but the acceleration is $$-g.$$

Question 12

A projectile is launched from the ground at an angle $$	heta$$ with initial speed $$v_0. $$Which of the following best describes the path of the projectile?

Accepted Answer

A parabola

Question 13

A helicopter is flying horizontally at $$11\ \mathrm{m/s}$$ and begins to accelerate upward at $$0.96\ \mathrm{m/s^2$}. $$What is the magnitude of its velocity at $$t = 5.3\ \mathrm{s}$$?

Accepted Answer

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

Question 14

A projectile is launched from the ground with $$v_0 = 20.0$$\ \mathrm{m/s}$$ at 35.0$$^\circ$$ above the horizontal. What is the y$-position at t = 0.500$$\ \mathrm{s}$$?

Accepted Answer

$$y = 4.52\ \mathrm{m}$$

Question 15

An eagle descends at a constant velocity of $$3.10\ \mathrm{m/s} at$$ $$20.0^\circ$$ below the horizontal from a height of $$19.5\ \mathrm{m}. $$What is the horizontal distance traveled when it reaches the water?

Accepted Answer

$$53.5\ \mathrm{m}$$

Two-Dimensional Kinematics: Motion in a Plane and Projectile Motion

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