Question 1

A ball is thrown horizontally from the top of a 42.1 m high cliff with an initial speed of 10 m/s. Neglecting air resistance, how far from the base of the cliff does the ball land?

Accepted Answer

$$29.1\ \mathrm{m}$$

Question 2

A soccer ball is kicked at an angle $$	heta$$ above the horizontal with an initial speed $$v_0. At $$the highest point of its trajectory, which of the following statements is true?

Accepted Answer

The ball's velocity is horizontal and its acceleration is downward.

Question 3

A rock is thrown from the upper edge of a hill off a cliff at some angle above the horizontal. It reaches its maximum height and then falls to the ground. Which of the following statements about its velocity at its highest point is correct?

Accepted Answer

Its vertical velocity component is zero.

Question 4

A 1200 kg car accelerates uniformly from $$0\ \mathrm{m/s} to$$ $$27.0\ \mathrm{m/s} in$$ $$10.0\ \mathrm{s}. $$What is the magnitude of the net force required?

Accepted Answer

$$3240\ \mathrm{N}$$

Question 5

A box of mass $$5.4\ \mathrm{kg} is $$being pulled along a horizontal smooth surface by a force of $$24\ \mathrm{N}$$ directed at an angle of $$22^\circ$$ above the horizontal. What is the magnitude of the normal force exerted on the box?

Accepted Answer

$$43.0\ \mathrm{N}$$

Question 6

A traffic light weighing $$100\ \mathrm{N} is $$supported by two ropes as shown in the figure, each making an angle of $$45^\circ$$ with the horizontal. What is the tension in each rope?

Accepted Answer

$$70.7\ \mathrm{N}$$

Question 7

A velocity vector has components $$36\ \mathrm{m/s}$$ westward and $$22\ \mathrm{m/s}$$ northward. What is the magnitude and direction of this vector?

Accepted Answer

$$42\ \mathrm{m/s}$$,\ 31^\circ$ north of west

Question 8

If you weigh $$741\ \mathrm{N} on $$Earth ($$g = 9.80\ \mathrm{m/s^2$}) $$and $$532\ \mathrm{N} on $$the surface of another planet, what is the acceleration due to gravity on that planet?

Accepted Answer

$$7.03\ \mathrm{m/s^2$}$$

Question 9

A block lies on a horizontal frictionless surface. A horizontal force of $$100\ \mathrm{N} is $$applied to the block, giving it an acceleration of $$3.33\ \mathrm{m/s^2$}. $$What is the mass of the block?

Accepted Answer

$$30.0\ \mathrm{kg}$$

Question 10

A displacement vector is $$14.0\ \mathrm{m} in $$length and is directed $$60.0^\circ$$ south of east. What are its $$x$$ and $$y$$ components?

Accepted Answer

$$x = 7.0\ \mathrm{m}$$,\ y = -12.1\ \mathrm{m}$

Question 11

A cat leaps to try to catch a bird. If the cat's jump was at $$60^\circ$$ off the ground and its initial velocity was $$2.74\ \mathrm{m/s}$$, what is the highest point of its trajectory, neglecting air resistance?

Accepted Answer

$$0.28\ \mathrm{m}$$

Question 12

An athlete competing in the long jump leaves the ground with a speed of $$9.14\ \mathrm{m/s} at an $$angle of $$30^\circ$$ above the horizontal. What is the length of the athlete's jump, assuming no air resistance?

Accepted Answer

$$8.53\ \mathrm{m}$$

Question 13

A spaceship in outer space (far from all gravity) suddenly stops its engines. The spaceship will:

Accepted Answer

Continue moving at constant velocity.

Question 14

The acceleration due to gravity is lower on the Moon than on Earth. Which of the following statements is true about the mass and weight of an astronaut on the Moon compared to Earth?

Accepted Answer

Mass is the same, weight is less.

Question 15

An object of weight $$W is in $$level elevator on the surface of Earth. The magnitude of the force that the object exerts on Earth is:

Accepted Answer

Equal to $$W$$

Question 16

Which of the following is a vector quantity?

Accepted Answer

The velocity of a car

Question 17

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity:

Accepted Answer

Remains constant

Question 18

If a vector $$\vec{A}$$ has components $$A_x  0$$, then the direction of the vector can best be described as:

Accepted Answer

Northwest

Question 19

An object is moving with constant non-zero velocity. Which of the following statements about the object must be true?

Accepted Answer

No net force is acting on the object.

Kinematics, Projectile Motion, and Forces: Study Guide with Problems and Solutions

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