Assertion: A tiger can accelerate from rest at the rate of 4m/s^2.

Reason: The velocity attained by it in 10s is 40m/s.

Explanation:

Acceleration is defined as the rate of change of velocity with respect to time. In other words, it measures how quickly an object's velocity is changing. It can be calculated using the formula:

Acceleration (a) = Change in velocity (Δv) / Time taken (Δt)

Let's analyze the given assertion and reason in detail:

1. Assertion: A tiger can accelerate from rest at the rate of 4m/s^2.

When it is stated that a tiger can accelerate from rest at the rate of 4m/s^2, it means that the tiger can increase its velocity by 4 meters per second every second. In other words, its velocity increases by 4 meters per second for every second of time.

2. Reason: The velocity attained by it in 10s is 40m/s.

The reason mentioned states that the velocity attained by the tiger in 10 seconds is 40m/s. This implies that if the tiger accelerates at a rate of 4m/s^2 for 10 seconds, its final velocity will be 40m/s.

To verify the validity of the reason, we can use the equation of motion:

Final velocity (v) = Initial velocity (u) + (Acceleration (a) * Time (t))

Assuming the initial velocity of the tiger is 0 m/s (since it starts from rest) and substituting the given values:

v = u + (a * t)
v = 0 + (4 * 10)
v = 0 + 40
v = 40 m/s

Therefore, the final velocity attained by the tiger after 10 seconds of acceleration at a rate of 4m/s^2 is indeed 40m/s.

Conclusion:

The given assertion is true, and the reason provided is also valid. A tiger can accelerate from rest at the rate of 4m/s^2, and the velocity attained by it in 10 seconds of acceleration is 40m/s.