JEE MAIN - Physics (2021 - 18th March Evening Shift - No. 24)
The projectile motion of a particle of mass 5 g is shown in the figure.
_18th_March_Evening_Shift_en_24_1.png)
The initial velocity of the particle is $$5\sqrt 2 $$ ms-1 and the air resistance is assumed to be negligible. The magnitude of the change in momentum between the points A and B is x $$\times$$ 10-2 kgms-1. The value of x, to the nearest integer, is __________.
The initial velocity of the particle is $$5\sqrt 2 $$ ms-1 and the air resistance is assumed to be negligible. The magnitude of the change in momentum between the points A and B is x $$\times$$ 10-2 kgms-1. The value of x, to the nearest integer, is __________.
Answer
5
Explanation
_18th_March_Evening_Shift_en_24_2.png)
$$|\overrightarrow u | = |\overrightarrow v |$$ .... (1)
$$\overrightarrow u = u\cos 45\widehat i + u\sin 45\widehat j$$ ..... (2)
$$\overrightarrow v = v\cos 45\widehat i - v\sin 45\widehat j$$ ..... (3)
$$|\Delta \overrightarrow P | = |m(\overrightarrow v - \overrightarrow u )|$$ .... (4)
$$\Delta P = 2mu\sin 45^\circ $$
$$ = 2 \times 5 \times {10^{ - 3}} \times 5\sqrt 2 \times {1 \over {\sqrt 2 }}$$
= 50 $$\times$$ 10$$-$$3
= 5 $$\times$$ 10$$-$$2
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