Question

By how much does the velocity of a train change in 20 seconds when accelerating at 2 m/s2 ?

By how much does the velocity of a car change in 5 seconds when accelerating at 4 m/s2 ?

Answer 1

Answer:

(a) The change in the velocity of the train is 40 m/s.

(b) The change in the velocity of the car is 20 m/s.

Explanation:

The acceleration is defined as,

$a=\frac{\text{ Change in the velocity}}{\text{ Time taken}}\\\therefore\text{Change in the velocity}=a\times\text{Time taken}$

(a) Given information:

• Time taken $t=20 \text{ s}$.
• Acceleration of the train $a=2\text{ m/s}^2$.

Therefore, the change in velocity of the train in 20 sec is,

$\text{ Change in the velocity}=2\text{ m/s}^2\times20\text{ s}\\=40\text{ m/s}$

(b) Given information:

• Time taken $t=5 \text{ s}$.
• Acceleration of the car $a=4\text{ m/s}^2$.

Therefore, the change in velocity of the car in 5 sec is,

$\text{ Change in the velocity}=4\text{ m/s}^2\times5\text{ s}\\=20\text{ m/s}$

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