The force that keeps two surfaces at rest from sliding over each other is

A heat engine produces 8200 j of heat while performing 3200 of useful work. what is the efficiency of this engine? (i'm doing something wrong.)

What is the momentum of a 453 gram football that is thrown with a speed of 30 M/s

A ball rolls down a ramp for 15 seconds. If the initial velocity of the ball was 0.8m/s and the final velocity was 7 m/sec, what was the acceleration of the ball?

Which star has the highest surface temperature? Group of answer choices Blue star Yellow star White star Red star

Potential energy is measured in units of

A car moving at a steady 10 m/s on a level highway encounters a bump that has a circular cross-section with a radius of 30 m. The car maintains its speed over the bump. What is the normal force exerted by the seat of the car on a 60.

Determine the magnitude of the force p required to hold the 180-kg crate in equilibrium.

Match the following: 12) Site where resistance to blood flow is greatest. 13) Site where blood pressure is lowest. 14) Site where exchanges of food and gases are made. 15) Site where the blood pressure is greatest.

How many trees were sold in all during 1999 and 2000?

a cannon sits on a stationary railroad flatcar with a total mass of 1000 kg. when a 10 kg cannonball is fired to the left at a speed of 50 m/s, what is the speed of the flatcar