Why is it impossible to create a perpetual motion machine?

According to newton's second law of motion, how much force will be required to accelerate an object at the same rate if its mass is reduced by half? A. No change in the amount of force is needed. B. Four times the amount of force is needed. C.

A truck covers 40.0 m in 7.10 s while smoothly slowing down to a final velocity of 2.75 m/s ... (a) Find the truck's original speed.

What kind of things rust

Example of a colloid?

In your own words, explain why sound waves cannot travel in space.

Janice has just measured the density of an object. Which value is possible? (Density: D = )

Based on how the book describes a heat pump in sec 16.3 how does a heat pump prove law of conservation of energy

When a gas in a container is squeezed to half its volume, its density?

A ballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s. As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s.

The power rating of a vacuum cleaner is 0.8 kilowatts. If you use the vacuum cleaner for 2.5 hours, how much energy does it use?