Question

Numerical Questions

1:- A force of 8N causes a displacement of 4 m in a body in the direction of force. Calculate the work done?
Answer:- 32Nm

2:- How much force is applied on a body when 200 joules of work is done in displacing the body through a distance of 5m.
Answer:- 40N

3:- A body of 2 kg is raised to 5m. Find the work done.(g=10m/s2).
[Hint: Here, Work done=gravational potential energy ;work =PE=mgh]
Answer:- 100 joules

4:- A body of mass 0.5kg is moving with a speed of 20m/s. Find the kinetic energy.
Answer:- 100 joules

5:- A moving body of mass 0.3kg has 60Joule of kinetic energy. Calculate the speed of the body.
Answer:- ??


6:- A machine does 384J of work in 2 minutes. What is the power of the machine?
[Hint: a:- convert 2 min into sec
b:- Use the formula,P=W/T ]
Answer:- 3.2 Watt.



I have written ans but pls help me to do this no in formula.​

Answer 1

Answer:

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Explanation:

Solutions -:

   Ans 1.  Work done = F x S

                                     = 8 x 4

                                    = 32 Joules or Nm

   Ans 2.  Work done = F x S

                                F  = $\frac{Work done }{distance }$

                                    =  $\frac{200 }{5}$ =  40 N

   Ans 3.  Work done = mgh

                                   = 2 x 10 x 5

                                   =  100 Joules

   Ans 4. Kinetic energy =  $\frac{mv^{2} }{2}$

                                         = 0.5 x 20 x 10  

                                        =  100 Joules

   Ans 5. Kinetic energy =  $\frac{mv^{2} }{2}$

                                    $v^{2}$ =  $\frac{120}{0.3\\}$

                                    $v^{2}$ = 400

                                    v = 20 m/s

  Ans 6. Power = Energy/ time

                          = $\frac{384}{2}$

                         = 192 Watt