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Kamila [148]
3 years ago
13

A 74.9 kg person sits at rest on an icy pond holding a 2.44 kg physics book. he throws the physics book west at 8.25 m/s. what i

s his recoil velocity? PLEASE HELP ME
Physics
1 answer:
never [62]3 years ago
4 0

Answer:

The recoil velocity is 0.2687 m/s.

Explanation:

∵ The person is sitting on an icy surface , we can assume that the surface is frictionless.

∴ There is no force acting acting on the person and book as a system in horizontal direction.

Hence , momentum is conserved for this system in horizontal direction of motion.

If 'i' and 'f' be the initial and final states of this system , then by principle of conservation of momentum(p)  -

p_{i}=p_{f}

System initially is at rest

∴p_{i}=0

∴ From the above 2 equations

p_{f}=0

We know that ,

Momentum(p)=Mass of the body(m)×velocity of the body(v)

Let m_{1} and m_{2} be the mass of the person and the book respectively and v_{1} and v_{2} be the final velocities of the person and book respectively.

∴p_{f}=m_{1}v_{1}+m_{2}v_{2}=0

From the question ,

m_{1} = 74.9 kg

m_{2} = 2.44 kg

v_{2} = 8.25 m/s

Substituting these values in the above equation we get ,

(74.9 × v_{1} )+ (2.44×8.25) = 0

∴v_{1}  = - 0.2687 m/s (Negative sign suggests that the motion of  the person is opposite to that of the book)

∴ The recoil velocity is 0.2687 m/s.

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