Elem Physics Test 2

Earth exerts a gravitational force of 7000 N on one of the communications satellites. What force does the satellite exert on Earth?

7000 N

The gravitational force between two metal spheres in outer space is 1800 N. How large would the force be if the two spheres were one-half as closer?

7200 N

If you double the radius of a sphere, its volume increases by what factor?

8

What centripetal acceleration (m/s^2) is required to follow a circular path with a radius of 50 m at a speed of 20 m/s?

8

A bowling ball rolls off the edge of a giants table at 15 m/s. If it takes 4 s for the ball to hit the ground, what is the height of the table?

80 m

If there is no net force acting on an object, its motion will be one with ______ acceleration.

zero

What is the net force on a 2000 kg car that is traveling in a straight line at a constant speed of 40 m/s?

zero

A car drives off a vertical cliff at a horizontal speed of 24 m/s. If it takes 5 s for the car to hit the ground, how far from the base of the cliff does it land?

120 m

In straight line motion the

acceleration is parallel (or antiparallel) to the displacement.

What is the acceleration ( m/s^2) due to Earth's gravity at a distance of 10 Earth radii from Earth's center?

0.1

Two spacecraft in outer space attract each other with a force of 20 N. What would the attractive force be if they were twice as far apart?

10 N

A football quarterback throws a long pass toward the end zone. Assume that you can neglect the effects of air resistance. At the instant the ball reaches its highest point, what is the acceleration of the ball (m/s^2)?

10 down

A 60-kg person on a merry-go-round is traveling in a circle with a radius of 3 m at a speed of 3 m/s. What is the magnitude of the net force experienced by this person?

180 N

Communications satellites are synchronous satellites that orbit Earth each

24 hours

If the force of friction on a child's wagon is 25 N, how much force must be applied to maintain a constant, non-zero velocity?

25 N

Forces of 4 N and 6 N act on an object. What is the minimum value for the sum of these two forces?

2N

What are the size and direction of the force that is the sum of a force of 3 N acting south and a force of 5 N acting north?

2N North

There are three forces acting on an object: 6 N to the left, 5 N to the right, and 3 N to the right. What is the net force acting on the object?

2N left

A 5 kg ball is thrown horizontally at a speed of 20 m/s. At the same time a 100 kg ball is dropped from the same height. Ignoring air resistance, which ball hits the ground first?

It is a tie

A gun is held horizontally and fired. At the same time the bullet leaves the gun's barrel an identical bullet is dropped from the same height. Neglect air resistance, Which bullet will hit the ground first?

It is a tie

In the law of universal gravitation the force _____ as the mass decreases and _____ as the distance decreases.

decreases ... increases

A football quarterback throws a long pass toward the end zone. Assume that you can neglect the effects of air resistance. At the instant the ball reaches its highest point, what is the direction of the net force on the ball?

down

At the same time, two objects freely fall from the same height, which one will touch ground first?

the heavier one

Earth is held in its orbit by the gravitational force of the Sun. Therefore, the force that the Sun exerts on Earth is _____ that Earth exerts on the Sun.

the same as

If you push on a railroad boxcar with a force of 300 N and it doesn't move, you can conclude that:

there is a total force of 300 N in the opposite direction

In two dimensional motion, what is the SAME factor in both directions?

time