Students were asked to answer a question at schools and to state what is most important for them to succeed. The one that response stood out from the rest was practice. People who usually are successful do not become successful by being born. They work hard and perseverance their lives to succeeding. This is how you can obtain your goals. beneath some question and answer examples that you would possibly utilise to boost your knowledge and gain insight that will help you to maintain your school studies.

## Question:

When 150 joules of work is done on a system by an external force of 15 newtons in 20. seconds, the total energy of that system increases by.

(1) 1.5 × 102 J

(2) 2.0 × 102 J

(3) 3.0 × 102 J

(4) 2.3 × 103 J

Please include an explanation

## Answer:

The total energy of that system increases by **150 Joule**. The correct answer is option (**1**)

Given that 150 joules of work is done on a system by an external force of 15 newtons in 20 seconds

**The impulse on the system = the momentum of the system**

That is,

Ft = mV

15 x 20 = mV

mV = 300 Ns

Since **work done = energy**

W = 1/2mV x V

150 = 0.5 x 300V

V = 1 m/s

With this, we can calculate the **acceleration** and the **distance travelled**.

Using equation one of motion,

**V = u + at**

1 = 0 + 20a

a = 1/20

a = 0.05 m/

Using equation three of linear motion.

= + 2aS

Substituting all parameters into the equation

= 0 + 2 x 0.05 S

S = 1/0.1

S = 10 m

**The work done = Force x distance**

The work done = 15 x 10

The work done = 150 Joule.

Therefore, the total energy of that system increases by **150 Joule**.

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