Projectile, Gravitation and Energy Review

A student throws a baseball upwards at an angle of 60 degrees to the horizontal. The initial horizontal and vertical components are 12.5 m/s and 21.7 m/s, respectively.

According to the information and diagram shown above, what position will have the greatest magnitude of vertical acceleration?

• A

• B

• C

• The magnitude of the acceleration is the same at all the positions.

At which point will the vertical velocity be zero?

• A

• B

• C

• The vertical (y) velocity will never change.

Two asteroids exert a gravitational force, F, on each other. Some time later, the asteroids are now three times as far from each other as before. Which of the following represents the gravitational force at this distance?

• F/2

• F/3

• F/6

• F/9

The force of attraction due to gravity between two objects is F’. If the distance between the two objects doubles and the mass of one object triples, the new gravitational force between them will be —

• 0.5F'

• 0.75F'

• 1.5F'

• 2.5F'

Which of the following is the minimum amount of work done by a hydraulic lift to raise a 150-kg aluminum block 2.0 m vertically?

• 75 N*m (J)

• 300 N*m (J)

• 1500 N-m (J)

• 2940 N*m (J)

A spring does 5.0 J of work on a 0.10-kg ball bearing in a pinball machine. The ball's resulting speed just after leaving the spring is —

• 0.5 m/s

• 1 m/s

• 10 m/s

• 15 m/s

If a powerlifter raises a 1,000 N weight a distance of 2.0 meters in 0.5 seconds, what is his power output?

• 1,000 W

• 2,000 W

• 3,000 W

• 4,000 W

The motion of roller coasters depends upon the conversion of potential and kinetic energy. A 100-kg car starts from rest at the top of a hill with a height of 50 m. Which of the following is this car's kinetic energy at the bottom of the hill?

• 150 J

• 5000 J

• 49,000 J

• 98,000 J