Q: The range $$R of a $$projectile launched with initial speed $$v_0 at an $$angle $$\theta$$ above the horizontal (neglecting air resistance) is given by:

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

Question 1

A dart is launched with a speed of $$16.0\ \mathrm{m/s} at an $$angle of $$30.0^\circ$$ above the horizontal. How many seconds elapse until the dart travels a horizontal distance of $$4.0\ \mathrm{m}$$? (Neglect air resistance.)

Accepted Answer

$$0.29\ \mathrm{s}$$

Question 2

A biologist aims a tranquilizer gun directly at a monkey hanging from a branch. The moment the gun is fired, the monkey lets go and begins to fall. Neglecting air resistance, what happens?

Accepted Answer

The dart will hit the monkey.

Question 3

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

Accepted Answer

A parabolic curve.

Question 4

The range $$R of a $$projectile launched with initial speed $$v_0 at an $$angle $$	heta$$ above the horizontal (neglecting air resistance) is given by:

Accepted Answer

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

Question 5

What happens to the range of a projectile as the launch angle $$	heta$$ increases from $$0^\circ to$$ $$90^\circ$$, assuming constant initial speed and neglecting air resistance?

Accepted Answer

It first increases, reaches a maximum at $$45^\circ$$, then decreases to zero at $$90^\circ.$$

Question 6

A ball rolls off a horizontal table with an initial speed of $$2.0\ \mathrm{m/s}. If $$the table is $$1.25\ \mathrm{m}$$ high, how far from the base of the table does the ball land? (Use $$g = 9.8\ \mathrm{m/s^2$}.)$$

Accepted Answer

$$2.0\ \mathrm{m}$$

Question 7

Which of the following is NOT a contact force?

Accepted Answer

Gravity

Question 8

A $$10\ \mathrm{kg}$$ box is pulled across a frictionless surface with a net force of $$50\ \mathrm{N} to $$the right. What is the acceleration of the box?

Accepted Answer

$$5.0\ \mathrm{m/s^2$}$$

Question 9

A person stands on a scale in an elevator that is accelerating upward. Which statement is true about the normal force $$N$$ exerted by the scale on the person?

Accepted Answer

$$N is $$greater than the person's weight.

Question 10

Two crewpersons pull a raft. Crewperson 1 pulls with a force of $$130\ \mathrm{N} at an $$angle of $$34^\circ$$ counterclockwise from the negative x-axis. Crewperson 2, on the opposite side, pulls at an angle of $$45^\circ$$ from the negative x-axis. What force should Crewperson 2 apply so that the total force on the raft is in the positive x-direction?

Accepted Answer

$$156\ \mathrm{N}$$

Question 11

Which of the following statements about Newton's third law is correct?

Accepted Answer

Action and reaction forces are equal in magnitude and opposite in direction.

Question 12

A person is stranded on a frictionless frozen lake. To reach the shore, they throw a boot away from the shore. What happens?

Accepted Answer

The person moves toward the shore.

Question 13

Which of the following is the correct expression for the gravitational force between two masses $$m_1$$ and $$m_2$$ separated by a distance $$r$$?

Accepted Answer

$$F = G \dfrac{m_1$ m_2$}{r^2$}$$

Question 14

If the distance between two planets is doubled, what happens to the gravitational force between them?

Accepted Answer

It becomes one quarter as large.

Question 15

A sled is pushed across a horizontal snowy surface and then released. After release, the sled gradually slows to a halt. Which force is primarily responsible for this?

Accepted Answer

Friction

Question 16

A car is moving on an icy road and tries to turn. What is most likely to happen?

Accepted Answer

The car will continue in a straight line due to inertia.

Question 17

Which of the following is a correct statement about the net force and acceleration of an object?

Accepted Answer

The acceleration is always in the direction of the net force.

Question 18

A $$5.0\ \mathrm{kg}$$ object is acted on by a net force of $$20\ \mathrm{N} at an $$angle of $$60^\circ$$ above the horizontal. What is the vertical component of the acceleration?

Accepted Answer

$$3.5\ \mathrm{m/s^2$}$$

Question 19

Which of the following best describes the direction of the tension force in a rope attached to a sled being pulled?

Accepted Answer

Away from the sled along the rope

Projectile Motion: Principles, Equations, and Applications

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