Question

1. Is it possible for a system to have negative gravitational potential energy?

a) Yes, as long as the kinetic energy is positive.

b) Yes, as long as the total energy is positive.

c) Yes, since the choice of zero of gravitational potential energy is arbitrary.

d) No, because the kinetic energy of a system must equal its gravitational potential energy.

e) No, because you can't have negative energy.

2. In an isolated system, for which of the following types of collision is the momentum of the system conserved?

a) an elastic collision

b) an inelastic collision

c) a perfectly inelastic collision

d) all of the above

e) none of the above

3. A piece of wood (with a volume of 75 cm3) is floating on water and is partially submerged. A piece of iron (with a volume of 75 cm3) is totally submerged and is sinking to the bottom. Which has the greater buoyant force acting on

a) the wood

b) the iron

c) Both have the same buoyant force

d) Neither have buoyant forces

e) Not enough information

4. A ball (0.125 kg) shoots into a wall at 50 m/s; it bounces away from the wall at 30 m/s. A high-speed camera shows that the collision took 0.1 seconds. What is the average force acting on the ball during the collision?

a) 25 N

b) 37.5 N

c) 62.5 N

d) 100 N

e) 200 N

5. A 1000-kg car has a velocity of -20 m/s (i.e. to the left). How much kinetic energy does the car have?

a) -200,000 J

b) -20,000 J

c) -10,000 J

d) 10,000 J

e) 200,000 J

Answer 1

1 c) concept based and common knowledge

2) D

3 Force is Density of liquid × submerged volume × gravitation acceleration.

So force is directly proportional to submerged volume .

So option B is answer.

For 4 th and 5th see pic.NEED THUMBS UP PLEASE HUMBLE REQUEST ANY DOUBT COMMENT. BUT GIVE THUMB'S UP PLEASE