A 200 kg crate is pulled along a level surface by an engine. the coefficient of friction between crate and surface is 0.4.

a. how much power must the engine deliver to move the crate at 5.0m/s.

b. how much work is done by the engine in 180s

How many years does one mouth symbolize on the cosmic calendar

car is travelling north at a constant speed of 20 m/s. A force is applied directly east on the car. The motion of the car will be change in which of these ways? A) The speed of the car will increase. B) The speed of the car will decrease.

When a 4.10-kg object is hung vertically on a certain light spring that obeys Hooke's law, the spring stretches 2.90 cm. If the 4.10-kg object is removed, how far will the spring stretch if a 1.50-kg block is hung on it?

How do the forces in nuclear and chemical reactions differ? A. Both reactions only need to overcome weak electrostatic forces. B. Chemical reactions must overcome the strong nuclear force. C. Nuclear reactions must overcome much stronger forces. D.

The small depression inside the bend of the elbow is the

A copper rod is 0.450 m long. Heat is added to the rod until it expands by 0.00130 m. How much did the temperature change? (Unit=C)

What often happens to light when it travels from one medium to another

60,000 is 100 time as much as

A balloon is expanded to the same volume as that of a human head. Do an order-of-magnitude estimate of the volume of this balloon in cm3.

Which of the following atoms do not usually form bonds