NEETPhysicsMotion in A PlaneMCQ+4 / −1
A car starts from rest and accelerates at 5m/s2. At t = 4 s, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at t = 6 s? (Take g = 10 m/s2)
- A20 m/s, 10 m/s2
- B20 m/s, 5 m/s2
- C20 m/s, 0
- D20 m/s, 0
View written solutionFree
Correct answer: A
u = 0
a = 5
t = 4
velocity of car at t = 4 sec is
V = u + at
V = 0 + 5 4
V = 20 m/s
For ball :
At t = 4 s, A ball is dropped out of a window so
velocity of ball at this instant is 20 ms–1 along
horizontal.
After 2 seconds of motion :
Horizontal velocity of ball , Vx = 20 m/sec
Vy = u + ut
= 10 2
Vertical velocity of ball, Vy = 20 m/sec
So magnitude of velocity of ball
V = = 20
and Acceleration of ball at t = 6 s is g = 10 m/sec2
As ball is under free fall.
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