Question

Assertion: If a particle is thrown upwards then distance travelled in last second of upward journey is independent of the velocity of projection.
Reason: In last second distance travelled is $4.9\text{m}$. (Take $g=9.8{\text{m/s}}^2$)

• A. Both assertion and reason are correct and reason is the correct explanation of assertion.
• B. Both assertion and reason are correct and reason is not the correct explanation of assertion.
• C. Assertion is correct and reason is incorrect.
• D. Assertion is incorrect and reason is correct.

Answer 1

The correct option is A Both assertion and reason are correct and reason is the correct explanation of assertion.

Distance travelled in the last second of upward journey is equal to the distance travelled in the first second of downward journey.
At the highest point, velocity of the particle is $0$
$\therefore$ Distance travelled in $1^{st}$ second of downward journey = $\frac{1}{2}g{t}^2$ (By second equation of motion)
$=\frac{1}{2}\times 9.8\times (1{)}^2$
$=4.9\text{m}$
Hence, distance travelled in last second of the upward journey is independent of the velocity of projection.
Reason is the correct explanation of assertion.