12.6 CHAPTER 12. FORCE,MOMENTUM AND IMPULSE
- An astronaut weighs 750 N on the surface of the Earth.
(a) What will his weight be on the surface of Saturn, which has a mass 100 times
greater than the Earth, and a radius 5 times greater than the Earth?
(b) What is his mass onSaturn?
- A piece of space garbage is at rest at a height 3 times the Earth’sradius above the
Earth’s surface. Determine its acceleration due to gravity. Assume the Earth’s mass is
6,0 x 10^24 kg and the Earth’s radiusis 6400 km.
- Your mass is 60 kgin Paris at ground level.How much less would you weigh after
taking a lift to the top of the Eiffel Tower, whichis 405 m high? Assumethe Earth’s
mass is 6,0 x 10^24 kg and the Earth’s radiusis 6400 km.
- (a) State Newton’sLaw of Universal Gravitation.
(b) Use Newton’s Lawof Universal Gravitationto determine the magnitude of the
acceleration due to gravity on the Moon.
The mass of the Moon is 7,40× 1022 kg.
The radius of the Moonis 1,74× 106 m.
(c) Will an astronaut, kitted out in his space suit, jump higher on the Moon or on
the Earth? Give a reasonfor your answer.
Momentum
- [SC 2003/11]A projectile is fired vertically upwards from the ground. At the highest
point of its motion, theprojectile explodes andseparates into two pieces of equal
mass. If one of the pieces is projected vertically upwards after the explosion, the
second piece will...
(a) drop to the ground at zero initial speed.
(b) be projected downwards at the same initial speed at the first piece.
(c) be projected upwards at the same initial speed as the first piece.
(d) be projected downwards at twice the initial speed as the first piece.
- [IEB 2004/11 HG1]A ball hits a wall horizontally with a speed of 15 m·s−^1. It
rebounds horizontally with a speed of 8 m·s−^1. Which of the following statements
about the system of theball and the wall is true?
(a) The total linear momentum of the system is not conserved during thiscollision.
(b) The law of conservation of energy does notapply to this system.
(c) The change in momentum of the wall is equal to the change in momentum of
the ball.
(d) Energy is transferredfrom the ball to the wall.
- [IEB 2001/11 HG1] Ablock of mass M collides with a stationary blockof mass 2M.
The two blocks move off together with a velocity of v. What is the velocity of the
block of mass M immediately before it collides with the block of mass 2M?
(a) v
(b) 2v
(c) 3v
(d) 4v
- [IEB 2003/11 HG1]A cricket ball and a tennis ball move horizontally towards you
with the same momentum. A cricket ball has greater mass than a tennisball. You
apply the same force instopping each ball.
How does the time taken to stop each ball compare?
(a) It will take longer tostop the cricket ball.
(b) It will take longer tostop the tennis ball.
(c) It will take the sametime to stop each of theballs.
(d) One cannot say howlong without knowing the kind of collision theball has
when stopping.
