Question

18. A body of mass 5 kg starts from the origin with an
initial velocity i =(301 + 40) ms!. If constant
force (-61-5) N acts on the body, the time in
which the y-component of the velocity becomes
zero is
(a) 55
(b) 20 $ (c) 40 (d) 80​

Answer 1

Answer:

Explanation:

Correct Question,

A body of mass 5 kg starts from the origin with initial velocity (30i + 40j) m/s. If a constant force (- 6i - 5j) N act on the body the time in which the Y component of the velocity becomes zero is

Solution,

Here, we have

Mass, m = 5 kg

Initial velocity, u = (30i + 40j) m/s

Final velocity, v = 0

Force, F = (- 6i - 5j) N

To Find,

Y component of the velocity in how much time.

According to the 2nd law of Newton,

We know that,

F = ma

a = F/m

So, putting all the values, we get

⇒ a = F/m

⇒ a = - 5/5

⇒ a = - 1 m/s²

Now, According to the 1st equation of motion,

We know that,

v = u + at

So, putting all the values again, we get

⇒ v = u + at

⇒ 0 = 40 + (- 1) × t

⇒ t = 40 × 1

⇒ t = 40 seconds.

Hence, the time taken by Y component of the velocity is 40 seconds.