1) Angular Position:When we look up at the sun it subtends an angle of about 0.5 . What is the radius of the Sun, if the Sun is 150 Million km (1.5x1011m) away? HINT: Convert 0.5o to radians.

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2) Circular Motion/ Centripetal acceleration:
Imagine that you swing a ball of 5 kg total mass around in a horizontal circle, so that it completes 1.5
revolutions per second. The weight is attached to you via a cord of negligible mass. The radius of the arc is 1.5 m.
a) What is the speed of the ball? Hint: speed = distance / time.
b) What is the ball's acceleration, and which way does the acceleration vector point?
c) What magnitude of the force exerted on the ball? d) What supplies this force?


3) Circular Motion/ Centripetal acceleration:
The Sun has a mass o f2.0x1030 kg.The Earth has a mass of 6.0x1024 kg and orbits the sun at a mean distance of 150 x 109 m. The gravitational force, F, acting on any mass m due to another mass M is given by;
F = GMm r2 ,
where r is the distance between the masses and G is a constant, G = 6.67 x 10-11 N.m2.kg-2.

a) Which is greater: the gravitational force of the sun on the Earth, or the Earth on the sun? Explain
your answer. HINT: Swap M and m in the equation above .....
b) What is the acceleration of the Earth due to the Sun? In what direction is this acceleration?
c) Give the above acceleration can you determine the speed of the Earth?
d) Using the above speed try to work out how long it takes for the Earth to complete a single orbit
around the sun.

4) Angular Kinematics:
An automobile engine slows down from 4500 rpm to 1200 rpm in 2.5 s.
a)What is 4500 rpm in rad/s? HINT: rpm is revolutions per minute
b)Calculate the average angular acceleration as the engine slows down
c) The total number of revolutions the engine makes in this time. Hint: Determine number of radians
first.

5) Torque:
Can a smaller force exert a greater torque than a larger force? Explain.

6) Torque:
Adult chimpanzees have muscle mass of only about 1 /3 of an adult human male, but it has been shown to be over twice as strong in some movements. Can you account for this? Hint: Think about attachment position of muscle to the bone at the elbow.

7) Static Equilibrium: Zoltan supports a 5 m long 10 kg beam at one end. The beam
is uniform in cross section and in density, and is supported at the other end by a bench.
a) What conditions must be satisfied for a rigid body to be in static equilibrium?
b) What force must Zoltan exert in order to keep the beam horizontal? Justify your answer.
HINT: There are 3 forces acting on the beam.