1. A force acting on an object does no work if

A a machine is used to move the object

B the force is not in the direction of the object's motion

c the force is greater than the force of friction

What factors might cause population changes in grasshoppers?

A horse is running at 12m/s accelerated to 38m/s in 10 seconds. What is the horses acceleration.

Which of the following substances will show the smallest change in temperature when equal amounts of energy are absorbed? water air sand concrete

Students in a physical education class practiced rope climbing. Students gripped a rope that hung from the ceiling and lifted themselves up the rope using only their arms.

A ramp is a simple machine called the a. wedge b. pulley c. inclined plane d. lever

Why does momentum have a direction?

What is the difference between weight and mass?

An object has a mass of 8.00 kg. What is the gravitational force on the object by the earth?

Which of the following best characterizes the free energy change ΔG for an endothermic reaction under physiological conditions? A. The sign of ΔG is positive B. The sign of ΔG is zero C. The sign of ΔG is negative D.

In a recent hockey game, one player (m=100kg) was moving at a velocity of 8 m/s when he ran into another player (m=300kg) who was at rest (v=0m/s). After the collision, the two players were stuck together (moving with the same velocity).