CHAPTER 12. FORCE,MOMENTUM AND IMPULSE 12.6
(a)^19 F
(b)^13 F
(c) 3 F
(d) 9 F
- [SC 2003/11] An object is dropped from aheight of 1 km above the Earth. If air
resistance is ignored, the acceleration of the object is dependent on the...
(a) mass of the object
(b) radius of the earth
(c) mass of the earth
(d) weight of the object
- A man has a mass of70 kg on Earth. He is walking on a new planetthat has a mass
four times that of the Earth and the radius is thesame as that of the Earth( ME= 6 x
1024 kg, rE= 6 x 10^6 m )
(a) Calculate the force between the man and theEarth.
(b) What is the man’s mass on the new planet?
(c) Would his weight be bigger or smaller onthe new planet? Explain how you
arrived at your answer.
- Calculate the distance between two objects,5000 kg and 6 x 10^12 kg respectively, if
the magnitude of the force between them is 3 x 10 ?8N.
- Calculate the mass of the Moon given that anobject weighing 80 N onthe Moon has
a weight of 480 N on Earth and the radius of theMoon is 1,6 x 10^16 m.
- The following information was obtained froma free-fall experiment todetermine the
value of g with a pendulum.
Average falling distancebetween marks = 920 mm
Time taken for 40 swings = 70 s
Use the data to calculatethe value of g.
- An astronaut in a satellite 1600 km above theEarth experiences gravitational force of
the magnitude of 700 Non Earth. The Earth’s radius is 6400 km. Calculate
(a) The magnitude of the gravitational force which the astronaut experiences in the
satellite.
(b) The magnitude of the gravitational force on an object in the satellite which
weighs 300 N on Earth.
- An astronaut of mass 70 kg on Earth landson a planet which hashalf the Earth’s
radius and twice its mass. Calculate the magnitude of the force of gravity which is
exerted on him on the planet.
- Calculate the magnitude of the gravitationalforce of attraction between two spheres
of lead with a mass of 10 kg and 6 kg respectively if they are placed 50mm apart.
- The gravitational force between two objectsis 1200 N. What is the gravitational force
between the objects if the mass of each is doubled and the distance between them
halved?
- Calculate the gravitational force between the Sun with a mass of 2 x 1030 kg and the
Earth with a mass of 6 x 1024 kg if the distance between them is 1,4 x 10^8 km.
- How does the gravitational force of attraction between two objects change when
(a) the mass of each object is doubled.
(b) the distance between the centres of the objects is doubled.
(c) the mass of one object is halved, and the distance between the centres of the
objects is halved.
- Read each of the following statements and say whether you agree or not. Give reasons
for your answer and rewrite the statement if necessary:
(a) The gravitational acceleration g is constant.
(b) The weight of an object is independent of its mass.
(c) G is dependent on the mass of the object that is being accelerated.
