# Christmas work

Mechanics second half.

Q1. Define the following terms: Weight, momentum, principle of conservation of momentum, centripetal force, simple harmonic motion, oscillation.

Q2. State Newton’s three laws of motion

Q3. A gun of mass 2 kg fires a bullet of 0.02g at 450 m/s. Find the recoil speed of the gun.

Q4. A block is submerged in water. The block is square and of side 15cm. It is at a depth of 1.25m in the water. Find the pressure at the top and the bottom of the block. Find also the force due to the water at the surface of the block. (water density = 1000 kg m3)

Q5. State the Archimedes principle.

Q6. State the law of floatation.

Q7. State Newton’s law of universal gravitation in words.

Q8. Find the value for gravity on a planet with mass 24x1024kg and a radius of 6x106m

G = 6.7x10-11.

Q9. A ball bounces from a height of 2.5 meters. It bounces and loses 5j of energy due to sound. If the ball has a mass of 2.25kg, what will the height of the second bounce be?

Q10. What is meant by the efficiency of a device with regard to its power output?

Q11. What is the force acting towards the centre of the circle if an object of mass 5kg moves with angular velocity 10 radians per second in a circle of radius 6m?

Q12. A satellite orbits the earth at a height of 60,000 km. What speed does it travel? How long does it take to make one revolution of the earth?