# Considering only the gravitational forces among the four objects, determine the magnitude and direction of the acceleration of the smaller object when it is released.

1.Three solid spheres of lead, each of mass 9.8 kg, are located at three corners of a square with side lengths of 50 cm. A small object is released at the forth corner. Considering only the gravitational forces among the four objects, determine the magnitude and direction of the acceleration of the smaller object when it is released.

2.A spy satellite is in circular orbit around the earth and makes four revolutions every day.

a)How high above the earth's surface is the satellite?

b) Calculate the satellite's speed?

3.A hand gun fires a 12.0 g bullet at a speed of 400 m/s.

What is its kinetic energy?

At what speed must a motorcycle of mass 173 kg move to have the same kinetic energy as the bullet? Express your answer in km/h.

4. A dinner plate of mass 510 g is pushed 60 cm along a dining table by a constant force of 3.0 N directed 22° below the horizontal. If the coefficient of kinetic friction between the plate and the table's surface is 0.44, determine the work done on the plate by

the applied force

the force of gravity

the normal force

the force of kinetic friction

5. A 15 kg block slides along a horizontal frictionless surface 3.0 m above the ground at a constant speed of 2.0 m/s. The block then slides down an incline that makes an angle of 35° with the horizontal and has a coefficient of kinetic friction equal to 0.30. After reaching the end of the incline, the block continues sliding horizontally across the frictionless ground. Calculate the kinetic energy of the block as it slides

a) along the upper surface.

b) along the ground.