Question

Force is applied to a body of mass $3 \text{ kg}$ at rest on a frictionless horizontal surface as shown in the force against time (F-t) graph. The speed of the body after $1 \text{ s}$ is

• A. 8 m/s
• B. 6 m/s
• C. 4 m/s
• D. 2 m/s

Hint:

Impulse = Area under $F-t$ graph = $m(v - u)$.

Answer 1

The Correct Option is D

Step 1: Concept
The area under a Force-Time ($F-t$) graph gives the impulse, which is equal to the change in momentum ($\Delta p = m \Delta v$).

Step 2: Meaning
Since the body starts from rest ($u=0$), the final speed $v = \text{Area} / m$.

Step 3: Analysis
Based on the graph provided in the source, the area under the curve from $t=0$ to $t=1 \text{ s}$ is calculated. For a mass of $3 \text{ kg}$, the impulse $J$ divided by 3 yields 2.

Step 4: Conclusion
The resulting speed is 2 m/s. Final Answer: (D)