Typical of Question 5 in Leaving Cert. Exam Q4 Answer all of the following parts (a), (b), (c), etc. (a) Define momentum.
(b) What is the momentum of a 70 kg man travelling at 8 m s1? (c) Define the term force.
(d) State Newton’s third law of motion. (e) Calculate the acceleration of a 25 kg body when a 100 N force is applied to it.
(f ) Two people pull in opposite directions on a body. Person A applies a 40 N force to the left, while B applies a 25 N force right. What is the net force on the body?
(g) The Earth is covered with a layer of air called the atmosphere.What holds this layer of air close to the Earth?
(h) An astronaut has a mass of 80 kg. Calculate his weight on the surface of the Moon. (Acceleration due to gravity on the Moon is 1.6 m s2.)
(i) A block of wood is dragged along a horizontal table by a rope angled at 22.62 to the horizontal. The tension in the rope is 26 N. Calculate the horizontal and vertical components of the force.
(j) A 4 kg bowling ball travelling at 9 m s1 hits a 6 kg ball at rest.The impact causes the lighter ball to stop.What speed does the heavier ball travel off at?
(7) (7) (7) (7) (7)
(7) (7) (7) (7) (7)
‘SECTION B’
FULL QUESTION Q5 State the principle of conservation of momentum.
Describe an experiment to demonstrate the principle of conservation of momentum.
A man of mass 72 kg is sliding across an ice rink.While skating in a straight line he throws a 6 kg bowling ball directly to his right-hand side (perpendicularly to his direction of motion) at a speed of 12 m s1.In order for the conservation of momentum to hold true, the man moves away to the left upon releasing the ball. Calculate his speed in this direction.The effects of friction may be ignored in calculating his new speed.
If the skater was originally travelling at 7 m s1, calculate his speed after releasing the ball. If the ice provided a frictional force on the man of 7212 N, how long would it take the man to
