A body was moving with a constant velocity of 20 m/s. When an external force is applied, it produces an uniform acceleration of $4 m / s^{2}$ . What is the time taken to reach 80 m/s and also find the velocity at half of that time? [3 MARKS]

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Solution

Finding Time : 1.5 Marks
Finding Velocity : 1.5 Marks

Here,

$u = 20 m / s, v = 80 m / s, a = 4 m / s^{2}$

We know, $a = \frac{v - u}{t}$

Using Equation, $v = u + a t$
$80 = 20 + (4 \times t)$
$4 t = 60$
$t = 15 s$
Therefore, time taken to reach $80 m / s$ is $15 s$ .

Velocity at $7.5 s$
$v = 20 + 4 \times 7.5 = 50 m / s$

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A body was moving with a constant velocity of 20 m/s. When an external force is applied, it produces an uniform acceleration of 4 m/s2. What is the time taken to reach 80 m/s and also find the velocity at half of that time? [3 MARKS]

Finding Time : 1.5 Marks Finding Velocity : 1.5 Marks Here, u=20 m/s, v=80 m/s, a=4 m/s2 We know, a=v−ut Using Equation, v=u+at 80=20+(4×t) 4t=60 t=15 s Therefore, time taken to reach 80 m/s is 15 s. Velocity at 7.5 s v=20+4×7.5=50 m/s

A body was moving with a constant velocity of 20 m/s. When an external force is applied, it produces an uniform acceleration of $4 m / s^{2}$ . What is the time taken to reach 80 m/s and also find the velocity at half of that time? [3 MARKS]