Question

q)read the given statement and select the correct option.
statement 1: an object thrown vertically up with a velocity u reaches the maximum height h after T seconds its velocity became zero.
statement 2: an object thrown vertically up with a velocity comes back to its initial position with same magnitude of velocity but in opposite direction.
A)both statements 1 & 2 are true and statement 2 is the correct explanation of statement 1.
B) both statements 1 & 2 are true but statement 2 is not the correct explanation of statement 1.
C) statement 1 is true but statement 2 is false.
D) statement 1 is false but statement 2 is true.​

Answer 1

Statement 1 :

An object thrown vertically up with a velocity u reaches the maximum height h after T seconds its velocity becomes zero

Yes , Statement 1 is true

This is because whenever an object is thrown upward with an initial velocity , gravitational acceleration acts on the body downwards and tries to decrease its velocity.

Finally, highest point is reached such that the velocity of the particle becomes zero and the height at which it is achieved is known as the maximum height.

Statement 2 :

An object thrown vertically upwards with a velocity returns back to its initial position with same magnitude of velocity but in opposite direction.

Yes , the statement is true

This is because , whenever the object is thrown upwards, it achieves zero velocity at its maximum height. After this the direction of its velocity reverses and the gravitational acceleration acts on the body for a same amount of time.

As a result , the body again reaches back to the ground with same magnitude of velocity but the direction is reversed and now direct downwards.

So , both statements are true , but statement 2 is not the correct explaination of statement 1.

Answer 2

Question:-

Statement 1: An object thrown vertically up with a velocity u reaches the maximum height h after T seconds its velocity became zero.

Statement 2: an object thrown vertically up with a velocity comes back to its initial position with same magnitude of velocity but in opposite direction.

A)both statements 1 & 2 are true and statement 2 is the correct explanation of statement 1.

B) both statements 1 & 2 are true but statement 2 is not the correct explanation of statement 1.

C) statement 1 is true but statement 2 is false.

D) statement 1 is false but statement 2 is true.

Answer:-

Statement 1:

This is because, due to acceleration due to gravity which acts in downwards direction on the body (-9.8m/s², -ve shows downward direction), the body slows down. The body goes up upto some extent because of its initial velocity u, but acceleration due to gravity reduces it's velocity and it becomes 0. At that time it reaches its maximum height. After that the velocity becomes less than 0 and it travels in downward direction.

Statement 2:

In (1), displacement comes +ve as final position is above the initial position

In (2), magnitude of displacement will be same [because distance from A to B = distance from B to C], but sign will be negative as final position will be below initial position.

$\bigstar$ Final velocity of motion from A to B = v' = Initial velocity of motion from B to C = u' = 0

So we can proof that v = - u

We can also proof that time of ascent = time of descent

Ans. B) both statements 1 & 2 are true but statement 2 is not the correct explanation of statement 1.