Question

Tom (mt = 2.00 kg) is chasing Jerry (m) = 0.400 kg). As you can see, both are running toward the right. Tom's velocity is VT = 2.50 m/s. Answer the two questions using three significant figures. Part A: How fast would Jerry have to be running in order for the value of his momentum to be equal to Tom's momentum? Number Vj = Part B: How fast would Jerry have to be running in order for the value of his kinetic energy to equal Tom's kinetic energy? Number

Answer 1

Given Tom's mass,

mt = 2kg

Jerry's mass, $m_{J}=0.4kg$

Tom's velocity,

UT = 2.50m)s

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Part A

Given that Jerry's momentum is equal to Tom's momentum

$p_{J}=p_{T}$

$m_{J}v_{J}=m_{T}v_{T}$

$v_{J}=\frac{m_{T}v_{T}}{m_{J}}$

$v_{J}=\frac{2kg*2.50m/s}{0.4kg}$

$v_{J}=\frac{2*2.50}{0.4}$

ANSWER: ${\color{Red} v_{J}=12.5m/s}$

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Part B

Given that Jerry's Kinetic energy is equal to Tom's Kinetic Energy

$KE_{J}=KE_{T}$

$\frac{1}{2}m_{J}v_{J}^{2}=\frac{1}{2}m_{T}v_{T}^{2}$

$m_{J}v_{J}^{2}=m_{T}v_{T}^{2}$

$v_{J}=\sqrt{\frac{m_{T}v_{T}^{2}}{m_{J}}}$

$v_{J}=\sqrt{\frac{2kg*(2.50m/s)^{2}}{0.4kg}}$

$v_{J}=\sqrt{\frac{2*2.50^{2}}{0.4}}$

ANSWER:
Uj=5.59m/s

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