A mechanical device requires 500j of work to do 200j of work in lifting a box. What is the efficiency of the device?

Write an argumentative paragraph supporting evolution.

Newton's second law states that the force on a drag racer is equal to the mass of the car times its acceleration. one of the most important factors determining the cars acceleration is the tires on the car.

A large block of ice is moving down the hill toward you at 25.0 m/s. Its mass is 125 kg. It is sliding down a slope that makes a 30.0 degree angle with the horizontal. In short: Think avalanche.

How can pieces of rock in contact with a stream bed move?

You're going 70mph, how long does it take to go 70 miles

Block B has mass 4.00 kg and sits at rest on a horizontal, frictionless surface. Block A has mass 2.00 kg and sits at rest on top of block B. The coefficient of static friction between the two blocks is 0.400.

T=2π√ (l/g) is dimensionally correct

A penny falls from a windowsill which is 25.0 m above the sidewalk. How much time does a passerby on the sidewalk below have to move out of the way before the penny hits the ground?

Show that the Newton has the units of mass times acceleration.

Light travels at 150000000km from the sun to earth in 8 minutes. What speed is this in Km/s