Question

A 10 kg stone is suspended by a string of breaking strength 300N. the minimum time in which the stone ca n be raised to a height of 10 meters is $( g = 10 ms^{-1} )$
A) 0.2 sec
B) 1 sec
C) 1.4 sec
D) 2.4 sec
Please give an accurate answer

Answer 1

Answer:

Correct option is

B

1.0 s

Maximum acceleration allowed after which the rope breaks =

m

F

max

=

10

30×10

=30 m/s

2

Acceleration due to gravity is already present due to suspension of stone.

Thus acceleration upto which the stone can be lifted with = a

max

−g=a=20 m/s

2

s=

2

1

at

2

⟹t=

a

2s

=

20

2×10

=1 s