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6. (JEE Main 2022 (Online) 27th July Morning Shift )

A bullet is shot vertically downwards with an initial velocity of 100   m / s from a certain height. Within 10 s, the bullet reaches the ground and instantaneously comes to rest due to the perfectly inelastic collision. The velocity-time curve for total time t = 20   s will be:

(Take g = 10 m/s2).

A. JEE Main 2022 (Online) 27th July Morning Shift Physics - Motion Question 45 English Option 1

B. JEE Main 2022 (Online) 27th July Morning Shift Physics - Motion Question 45 English Option 2

C. JEE Main 2022 (Online) 27th July Morning Shift Physics - Motion Question 45 English Option 3

D. JEE Main 2022 (Online) 27th July Morning Shift Physics - Motion Question 45 English Option 4

Correct Option is (A)

| v 10 | = ( 100 + 10 × 10 ) m/s

v 10 = 200 m/s and v 0 = 100 m/s

from 10s to 20s velocity remains zero

from t = 0s to 10s velocity increases in magnitude linearly.

graph given in option A fits correctly.

   

7. (JEE Main 2021 (Online) 18th March Evening Shift )

The velocity displacement graph of a particle is shown in the figure.

JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion Question 86 English
The acceleration displacement graph of the same particle is represented by :

A. JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion Question 86 English Option 1

B. JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion Question 86 English Option 2

C. JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion Question 86 English Option 3

D. JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion Question 86 English Option 4

Correct Option is (A)

The slope of the given v versus x graph is m = v 0 x 0 and intercept is c = + v0. Hence, v varies with x as

v = ( v 0 x 0 ) x + v 0 ...... (1)

where v0 and x0 are constants of motion. Differentiating with respect to time t, we have

d v d t = ( v 0 x 0 ) d x d t

or a = ( v 0 x 0 ) v ........ (2)

Using Eq. (1) in Eq. (2), we get

a = ( v 0 x 0 ) ( v 0 x 0 x + v 0 )

a = ( v 0 x 0 ) 2 x v 0 2 x 0

Thus the graph of a versus x is a straight line having a positive slope = ( v 0 x 0 ) 2 and negative intercept = v 0 2 x 0 . Hence the correct choice is (a).

   

8. (JEE Main 2021 (Online) 18th March Morning Shift )

The position, velocity and acceleration of a particle moving with a constant acceleration can be represented by :

A. JEE Main 2021 (Online) 18th March Morning Shift Physics - Motion Question 88 English Option 1

B. JEE Main 2021 (Online) 18th March Morning Shift Physics - Motion Question 88 English Option 2

C. JEE Main 2021 (Online) 18th March Morning Shift Physics - Motion Question 88 English Option 3

D. JEE Main 2021 (Online) 18th March Morning Shift Physics - Motion Question 88 English Option 4

Correct Option is (B)

Acceleration(a) is constant

v t (straight line graph)

and x t2 (parabolic graph)

   

9. (JEE Main 2021 (Online) 17th March Morning Shift )

A car accelerates from rest at a constant rate α for some time after which it decelerates at a constant rate β to come to rest. If the total time elapsed is t seconds, the total distance travelled is :

A. 4 α β ( α + β ) t 2

B. 2 α β ( α + β ) t 2

C. α β 2 ( α + β ) t 2

D. α β 4 ( α + β ) t 2

Correct Option is (C)

JEE Main 2021 (Online) 17th March Morning Shift Physics - Motion Question 91 English Explanation
t 1 + t 2 = t , V = 0 + α t 1

V = u + a t

0 = α t 1 β t 2

t 2 = α β t 1 = t

t 1 = ( β α + β ) t

Distance = 1 2 ( t 1 + t 2 ) × α t 1 (area of triangle)

= 1 2 t × α ( β α + β ) t

= α β 2 ( α + β ) t 2

   

10. (JEE Main 2021 (Online) 16th March Morning Shift )

The velocity-displacement graph describing the motion of bicycle is shown in the figure.

JEE Main 2021 (Online) 16th March Morning Shift Physics - Motion Question 94 English
The acceleration-displacement graph of the bicycle's motion is best described by :

A. JEE Main 2021 (Online) 16th March Morning Shift Physics - Motion Question 94 English Option 1

B. JEE Main 2021 (Online) 16th March Morning Shift Physics - Motion Question 94 English Option 2

C. JEE Main 2021 (Online) 16th March Morning Shift Physics - Motion Question 94 English Option 3

D. JEE Main 2021 (Online) 16th March Morning Shift Physics - Motion Question 94 English Option 4

Correct Option is (A)

We know that, a = v d v d x

as slope is constant, so a v (from x = 0 to 200 m)

& slope = 0 so a = 0 (from x = 200 to 400 m)

JEE Main 2021 (Online) 16th March Morning Shift Physics - Motion Question 94 English Explanation