Question

10. Two balls are thrown vertically upwards
simultaneously with different speeds. The variation
of their relative separation (AY) with time is best
represented by (Assume no rebouncing after hitting
ground)​

Answer 1

Answer:

(4) is correct option.

Explanation:

Before ball with lesser velocity hits the ground.

1) When two balls are thrown vertically upwards simultaneously with different speeds, then relative acceleration between them is 0.

Hence, Relative velocity is constant .

And, Direction of relative velocity changes from upward to downward in their journey.

=> Sign of relative velocity changes in upward to downward motion.

Slope in $\Delta Y\:\:Vs\:\: t$ (Relative Velocity ) is constant in upward and downward journey.

=> Graph in  $\Delta Y\:\:Vs\:\: t$  is linear in time.

2) After ball with lesser velocity hits the ground,

Relative acceleration is 'g' acting downward.

Relative acceleration is -10 units.

Hence, Relative velocity is linear and therefore, relative separation is quadratic in time .

Final Relative separation is 0.

=> Graph of relative separation is quadratic with  x-intercept when remaining ball hits the ground.

Finally, combining both (1) and (2) , Option (4) is correct .

Answer 2

Answer:

Graph 4

Explanation:

Time 40 m/s  50 m/s ΔY

0         0          0         0

1         35         45         10

2         60         80         20

3         75         105         30

4         80         120         40

5         75         125         50

6         60         120         60

7         35         105         70

8         0         80         80

9         0         45         45

10         0         0          0

The variation of their relative separation is linear  till ball with less velocity reaches the ground

but after that The variation of their relative separation is not linear

so Graph 4 is correct option