Question

2.
The moment of inertia of a body about a given axis is 2.4 kg-m2. To produce a rotational kinetic
energy of 750 J, an angular acceleration of 5 rad/s2 must be applied about that axis for
(1) 6 sec
(2) 5 sec
(3) 4 sec
(4) 3 sec​

Answer 1

Answer:

2s

Explanation:

KE=2Iω2

1500=21.2×ω2→ω=50

ωo=0

ω=ωo+αt=25t=50

t=2sec

Answer 2

Answer:

Hi, here is your answer,

Explanation:

I=2.4kg/m²

Rotational K.E= 750J

α= 5 rad/s²

K.E= Iω²/2

So, apply the given values.

You'll get ω= 25 rad/s

Consider the body starting its motion from rest. Then its initial angular velocity is zero,

ω0 = 0

Using the equation of rotational motion,

ω=ω0 + αt

25=0+5xt

t=25/5

t=5s

I hope that my explanation is clear to you.

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Thanks!