Page 84 - Force 10

Give Reasons;
20. The fall of a body on the earth’s surface cannot be a complete free

fall. why? OR is free fall possible on the surface of the earth, why?

The free fall is condition in which the object is falling only the influence

of gravity, so that the acceleration produced in free falling object must

be equal to the acceleration due to gravity of the earth. But on the

surface of the earth, presence of atmosphere provides resistance, thus

an upthrust to the falling object which decrease the acceleration of

falling object. Hence, the falling of a body on the earth’s surface cannot

be a complete free fall.

Q.21. Why can’t we fall safely with the help of parachute towards the moon ?

The moon does not have atmosphere on its surface, due t absence of

air resistance, the parachute does not open and its fall freely on the

surface of the moon with the acceleration equal to the acceleration due

to gravity of the moon with the increasing velocity. As a result, we with

parachute immediately falls on land with greater velocity and thus gets a

greater reaction force on the surface of the moon. Therefore, we can’t

fall safely with help of parachute towards the moon.