Question

7. A force acting on a body of mass 2 kg varies with
time as shown in Fig. 5.11. Find (i) impulse of the
force and (ii) the final velocity of the body.
[Ans. (i) 12 kg ms-1 (ii) 6 ms-11

Answer 1

Answer:

impulse is force×time

impulse can be find out using force -time graph by simply finding the area covered by graph...

here...

Explanation:

(1/2×2×4) +(1×4) +(1/2×2×4)

answer will be..

4+4+4

=12Ns

so final answer is 12Ns.

answer is 10Ns

and impulse is change in momentum

m(v-u) =12

2(v-0)=12

2v=12

v=6m/s

final answer is 6m/s

Answer 2

Answer:

(i) 12 Ns

(ii) 6 m/s

Explanation:

(i) Impulse (J) = Area under the curve

or                J = (1/2 × 2 × 4) + (1 × 4) + (1/2 × 2 × 4)

or                J = 4 + 4 + 4

or                J = 12 Ns or 12 kgm/s

(ii) Impulse (J) = Change in momentum (Δp)

or                J = m × (v-u)

or                12 = 2 × (v-0)                                            [ Initial Velocity (u) = 0]

or                2v = 12

or                 v = 6 m/s