What kind of simple machine is a catapult?

Why is perpetual energy possible?

What does the atomic number tell us about an atom of a certain element?

A current of 250 amps is flowing through a copper wire with a resistance of 2.09 x 10^-4 ohms. What is the voltage?

Planet z-34 has a mass equal to one-third that of earth and a radius equal to one-third that of earth. with g representing, as usual, the acceleration due to gravity on the surface of earth, the acceleration due to gravity on the surface of z-34 is

You are on top of a building that is 75.0 m tall. You toss a ball straight up with an initial velocity of 33.8 m/s. It goes up and then falls down to the ground below. How much time is it in the air?

an electric clothes dryer has a resictance of 16 Ohms it drawes 15 A of current what is the voltage in volts of the wall outlet that it is pluged into

A lorry with a mass of 5000kg accelerates to overtake a caravan on the motorway. Its acceleration is 1.5m/s². What force must the engine be providing? You can ignore the effects of friction and air resistance

Norma kicks a soccer ball with an initial velocity of 10.0 meters per second at an angle of 30.0% if the ball moves though the air for 3.2 seconds what's the horizontal distance traveled by the ball

Suppose s (t) is the position of an object moving along a line at time t is greater than or equal to 0. What is the average velocity between the times t=a and t=b? What is the instantaneous velocity at t=a?

Estimate how long it would take one person to mow a football field using an ordinary home lawn mower. suppose that the mower moves with a 1-km/h speed, has a 0.5-m width, and a field is 360 ft long and 160 ft wide. 1 m = 3.281 ft.