A hunk of cast concrete

Question 1

A hunk of cast concrete with a weight of 10 N will float if it displaces 11 N of water.

 True/false

Question 2

The density of a solid ball with a mass of 231 g and a volume of 110 cm^3 is ____ g/cm^3

1.182

25,410

2.10

0.476

Question 3 

If the distance from the Sun varied during an asteroid’s orbit, would its kinetic energy change? Would its potential energy change? Would the total energy (sum of kinetic and potential energy) of the asteroid change?

kinetic energy changes, potential energy does not change, and total energy changes

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kinetic energy does not change, potential energy changes, and total energy changes

kinetic energy changes, potential energy changes, and total energy changes

Question 4 

The “law of conservation of energy” is part of a government regulated policy on energy usage.

True/false 

Question 5 

Work is equal to _____ .

the change in kinetic energy of an object

force multiplied by the distance an object has moved

both answers above

none of the answers above

Question 6 

Power is _____ .

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typically measured in kW • hr

both answers above

none of the answers above

Question 7 

Evaluate (1.70×10^8)(5.900×10^-16). Be sure to follow the guidelines for entering answers in scientific notation.

Report your answer to 2 decimal places using scientific notation in the textboxes below.

Only one number should be to the left of the decimal point!

n.nn x 10^n

Question 8 

A 1,500 kg car moving at 7.0 m/s is stopped by the action of its brakes. The work done by the car’s brakes is ____ Joules.

Only enter your numerical answer below – do not include units. Report your answer to 2 decimal places.

Question 9 

The total energy of a 6.0 kg falling rock is 5000 J. If its potential energy is 2,150 J, the kinetic energy of the rock is ____ J.

Only enter your numerical answer below – do not include units.

Question 10 

If the kinetic energy of a 3.4 kg falling rock is 3,120 J, the rock’s speed is ____ m/s.

Only enter your numerical answer below – do not include units. Report your answer to 2 decimal places.

Question 11 

Assume an asteroid is in the shape of a sphere and has a mass of 1,200 kilograms. Determine the density (in grams per cubic centimeter) of this asteroid if its diameter is known to be 0.9 meters.

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Useful information: 1 kg = 1000 g, 1 m = 100 cm, volume of sphere = 4/3 ? r3. Remember that the radius of a sphere is equal to half its diameter!