Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 2

EASY

10th ICSE

IMPORTANT

Earn 100

A boy of mass $40 kg$ runs upstairs and reaches the $8 m$ high floor in $5 s$ . Calculate:
(i) the force of gravity acting on the boy.
(ii) the work done by him against gravity.
(iii) the power spent by the boy.
(Take $g = 10 m s^{- 2}$ )

Important Questions on Work, Energy and Power

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 3

It takes

20 s

for a person

A

to climb up the stairs, while another person

B

does the same in

15 s

. Compare the (i) Work done and (ii) power developed by the persons

A

and

B

.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 4

A boy weighing

350 N

runs up a flight of

30

steps, each

20 cm

high in

1 minute

, Calculate:
(i) the work done and
(ii) the power spent.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 5

A man spends

6.4 kJ

energy in displacing a body by

64 m

in the direction in which he applies force, in

2.5 s

. Calculate the force applied by the man.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 5

A man spends

6.4 kJ

energy in displacing a body by

64 m

in the direction in which he applies force, in

2.5 s

. Calculate the power spent (in H.P.) by the man.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 6

A weight lifter lifts a load of $200 kgf$ to a height of $2.5 m$ in $5 s$ . Calculate: (i) the work done, and (ii) the power developed by him.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 7

A machine raises a load of

750 N

through a height of

16 m

in

5 s

. Calculate:
(i) the energy spent by the machine,
(ii) the power of the machine if it is

100 %

efficient.

EASY

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 8

An electric heater of power

3 kW

is used for

10 h

. How much energy does it consume? Express your answer in (i)

kWh

, (ii)

joule

.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Physics For Class 10>Chapter 2 - Work, Energy and Power>EXERCISE-2(A)>Q 9

A boy of mass

40 kg

runs up a flight of

15

steps each

15 cm

high in

10 s

. Find the work done by the boy? Take

g = 10 N kg^{- 1}