Question

A 760 N man stands in the middle of a frozen pond of radius 6.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 1.2 kg physics textbook horizontally toward the north shore, at a speed of 6.0 m/s. How long does it take him to reach the south shore?

Answer 1

Step-by-step explanation:

Given

weight of man
`W=760 N`

mass of man
`m_1=(760)/(g)=76\ kg`

radius of pond
`r=6\ m`

mass of textbook
`m_2=1.2\ kg`

speed of text book
`v_2=6\ m/s`

Let speed at which man recoils is
`v_1`

Initially momentum is zero as man is at rest

Conserving momentum

`0=m_1v_1+m_2v_2`

`0=76* v_1+1.2* 6`

`v_1=-0.1\ m/s`

i.e. 0.1 m/s towards south

time taken to reach other side in absence of friction is given by

`t=(distance)/(speed)`

`t=(6)/(0.1)`

`t=60 s\approx 1\ minute`