Question

7. A force of 100 N acting on a body gives it a speed of 200 m/s in 2

sec. what is the mass of the body?
a. 1kg
b. 5 kg
c. 10kg
d. 15kg
​

Answer 1

a.1kg

Step-by-step explanation:

Answer 2

Choice a. 1 kg, assuming that all other forces on the object (if any) are balanced.

Step-by-step explanation:

By Newton's Second Law,

`\displaystyle a = (\Sigma F)/(m)`,

where

• 
  `a` is the acceleration of the object in
  `\text{m}\cdot\text{s}^(-2)`,
• 
  `\Sigma F` is the net force on the object in Newtons, and
• 
  `m` is the mass of the object in kilograms.

As a result,

`\displaystyle m = (\Sigma F)/(a)`.

Assume that all other forces on this object are balanced. The net force on the object will be
`100\;\text{N}`. The net force is constant. Acceleration should also be constant and the same as the average acceleration in the two seconds.

What is the average acceleration of this object?

`\displaystyle \begin{aligned}\text{Acceleration} &= \text{Average Acceleration}=\frac{\text{Change in Velocity}}{\text{Time Taken}}\end{aligned}`.

`\displaystyle {a} = \frac{200\;\text{m}\cdot\text{s}^(-1)}{2\;\text{s}}=100\;\text{m}\cdot\text{s}^(-2)`.

Apply Newton's Second Law to find the mass of the object.

`\displaystyle m = (\Sigma F)/(a) = \frac{100\;\text{N}}{100\;\text{m}\cdot\text{s}^(-2)} = 1\;\text{kg}`.