The given graph shows the time taken for a ping-pong ball to roll over the same distance over three different surfaces P, Q and R.
If the push and gravitational pull exerted on the ping pong ball are the same, which surface, P, Q or R is the smoothest?
DCannot be determined
Pointing to a photograph a person tells his friend, "She is the grand daughter of the elder brother of my father". How is the girl in the photograph related to the man?
DNone of these
she can be daughter also
Pallavi wants to find out whether the length of a ramp affects the force needed to move a wooden block up the ramp. She sets up the given experiment. What should she keep the same?
A The height of both the ramps
B The length of both the ramps
C The weight of spring balance
D Both (A) and (B)