If the floor is truly frictionless, then ANY force, no matter how small, applied for
ANY time, no matter how short, will set the block in motion. The force can then
be taken away, because on a frictionless surface, NO force is required in order
to keep the block moving.
The work done is equal to the kinetic energy you want the block to have. That
can be as much or as little as you feel like giving it.
Answer:
Gamma radiation or Cathode rays
Explanation:
by striking incident gamma or cathode rays onto the solid when placed on a photographic plate
Answer:
(c) time required to travel = 8 sec
Explanation:
We have given the final position = -10 m on x axis
And the initial position =10 m
So total distance = 10-(-10)=20 m
The speed is given as 2.5 m/sec
We have tof ind the time required by the person to travel
Time is given by
So the option (c) is correct option
Answer:
Explanation:
Let the distance be d . When sound travels d and is reflected back , it is heard by person as echo . Time taken by sound to travel total of distance 2 d
= 2 d / v where v is velocity of sound.
When this time is .05 s at least , echo will be heard . velocity of sound in air 340 m /s
so for echo to be heard ,
2 d / 340 = .05
d = 340 x .05 / 2
= 8.5 m .