Question

A car of mass 150 kg was pushed by two members with a net force 200N for 4Seconds. What is the change in the velocity of car?​

Answer 1

Answer:

5.33 m/s

Explanation:

As per the provided information in the given question, we have :

• Mass of the car (m) = 150 kg
• Net force (F) = 200 N
• Time taken (t) = 4 seconds

We are asked to calculate the change in velocity of the car.

⇒ Change in velocity = Final velocity – Initial velocity

⇒ Change in velocity = v – u

As we know that, according to the 2nd law of motion force is the product of mass and acceleration. That is,

$\\ \longrightarrow \quad \pmb{\boxed{\sf {F = ma}} }\dots \mathfrak{(1)}$

• m denotes mass
• a denotes acceleration

It is known to us that acceleration is defined as rate of change in velocity with time. Mathematically,

$\\ \longrightarrow \quad \pmb{\boxed{\sf { a = \dfrac{v-u}{t} }} }\dots \mathfrak{(2)}$

• v denotes final velocity
• u denotes initial velocity
• a denotes acceleration
• t denotes time

Here,

• (v - u ) denotes change in velocity.

Substituting the value of a from equation 2 to equation 1.

$\\ \longrightarrow \sf{\quad { F = m \times \dfrac{(v-u)}{t} }}$

Now, substitute all the values we have.

$\\ \longrightarrow \sf{\quad { 200 = 150 \times \dfrac{(v-u)}{4} }}$

$\\ \longrightarrow \sf{\quad { 200 \times 4 = 150 \times (v-u) }}$

$\\ \longrightarrow \sf{\quad { 800 = 150 \times (v-u) }}$

$\\ \longrightarrow \sf{\quad { \dfrac{800}{150} = (v-u) }}$

$\\ \longrightarrow \bf{\quad {\underline{ 5.33 \; m/s = (v-u)} }}$

Therefore, change in velocity of car is 5.33 m/s.

Answer 2

Mass = 150 kg

Net force = 200 N

∵ a = F/m = (200 kg m/s²)/(150 kg) = 4/3 m/s²

Now,

a = ∆v/t

⇒ ∆v = at

⇒ ∆v = 4/3 m/s² × 4 s

⇒ ∆v = 16/3 m/s or 5.33 m/s (answer).

Therefore, change in velocity is of 5.33 m/s.

More: Greek letter delta (∆) in Physics means 'change in'.