Question

(A) Acceleration between 10-15 sec.
(B) What is the force applied from 0-5 sec?
(C) Momentum after 10 sec.
(D) Nature of force between 25-30 sec.
(E) Magnitude of force between 15-25 sec.​

Answer 1

Answer:

Explanation:(a)Since velocity is not changing, acceleration is equal to zero.

(b) Reading the graph, velocity=20ms  

−1

 

(c) s = area of the figure enclosed under v-t graph. Distance covered in 15s, s=ut=20×15=300m

Answer 2

Explanation 1

If we look at the graph carefully, we see that, at $t=10s$ , the velocity is $10m/s$ whereas at $t=15s$, it is $20m/s$.

Hence, for acceleration between $t=10s$ to $t=15s$,  we have

$u=10m/s$  ; $v=20m/s$  ; $t=(15-10)=5s$

Hence,

$a=\frac{v-u}{t}$

$a=\frac{20-10}{5}$  $;$ $or$

$a=2m/s^{2}$

Explanation 2

We know, according to Newton's second law of motion, $F=\frac{dP}{dt}$ , where $dP$ is the change in momentum.

$F=m\frac{dv}{dt}$    ; m is the mass of the body

For the rate of change in momentum between $t=0s$ to $t=5s$, we have

$u=0m/s$   $;$  $v=10m/s$   $;$ $t=(5-0)=5s$   $;$ $m=20kg$

Therefore, force between $t=0s$ to $t=5s$ is

$F=20\frac{(10-0)}{5}$

$F=40N$

Hence, the force applied in the interval will be 40 N.

Explanation 3

Momentum of the body after $10s$ will be the product of the mass of the body and the velocity attained by the body after $10s$.

We have,

$m=20kg$   $;$  $v=10m/s$

Therefore,

Momentum $(P)=mv$

$P=20(10)$

$P=200kgm/s$

Hence, the momentum of the body after 10 s will be 200 kg m/s.  

Explanation 4

According to Newton's second law of motion,

$F=\frac{dP}{dt}$

$F=m\frac{dv}{dt}$

For force between $t=25s$ to $t=30s$ , we have

Velocity at $t=25s$ , is $20m/s$ and velocity at $t=30s$ is $0m/s$.

Therefore,

$F=20\frac{(0-20)}{5}$

$F=-80N$

Hence, negative force is attained which is due to deceleration or negative acceleration of the body.

Explanation 5

Newton's second law of motion,

$F=m\frac{dv}{dt}$

We have at $t=15s$, velocity $u=20m/s$ ; and

At $t=25s$, velocity $v=20m/s$ .

Time $t=(25-15)=10s$

Mass $=20kg$

Substituting the given values in the equation, we get

$F=20\frac{(20-20)}{10}$

$F=0N$

Hence, no force acts on the body in the given time interval.

Although your question is incomplete, you might be referring to the question below.

From the given graph of an object of mass 20 kg, answer the following questions.

1. Find acceleration between 10-15 sec.
2. Find the force applied from 0-5 sec.
3. Find momentum after 10 sec.
4. State the nature of the force between 25-30 sec.
5. Find the magnitude of force between 15-25 sec.