Physics Test 4

Result

Physics Test 4

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
4 / -1

A small sphere of mass m is dropped from a great height. After it has fallen 100 m, it has attached its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is–

A
Greater than the work done by air friction in the second 100 m

B
Less than the work done by air friction in the second 100 m

C
Equal to 100 mg

D
Greater than 100 mg

Solution

When a small sphere of mass m falls, its velocity goes on increasing till its weight (mg) is balanced by frictional forces (viscous forces) and it attains terminal velocity V_T.

In the first 100 m fall, when it attains V_T magnitude of frictional forces is small, There fore work done against frictional forces is less than the work done in second 100 m fall.