Science

PhysicsQ&A LibraryA boy of mass mb and his girlfriend of mass mg, bothwearing ice skates, face each other at rest while standing ona frictionless ice rink. The boy pushes the girl, giving her avelocity vg toward the east. Assume that mb > mg. (a) Describethe subsequent motion of the boy. (b) Find expressions forthe final kinetic energy of the girl and the final kinetic energyof the boy, and show that the girl has greater kinetic energy thanthe boy. (c) The boy and girl had zero kinetic energy before theboy pushed the girl, but ended up with kinetic energy after theevent. How do you account for the appearance of mechanicalenergy?Question

Asked Dec 18, 2019

39 views

A boy of mass m_{b} and his girlfriend of mass m_{g}, both

wearing ice skates, face each other at rest while standing on

a frictionless ice rink. The boy pushes the girl, giving her a

velocity v_{g} toward the east. Assume that m_{b} > m_{g}. (a) Describe

the subsequent motion of the boy. (b) Find expressions for

the final kinetic energy of the girl and the final kinetic energy

of the boy, and show that the girl has greater kinetic energy than

the boy. (c) The boy and girl had zero kinetic energy before the

boy pushed the girl, but ended up with kinetic energy after the

event. How do you account for the appearance of mechanical

energy?

Step 1

Let the initial velocity of the boy be denoted as *v _{1}* and the initial velocity of the boy be denoted as

From the law of conservation of linear momentum,

Step 2

Since initially both the girl and the boy are at rest *v*_{1 }and *v*_{2}, both will equal to zero.

From the above given information equation (1) can be rewritten as,

Step 3

From equation (2), it can be seen that velocity of the boy will be in the direction opposite to that of the girl.

So the velocity *vb* of the boy wil...

Tagged in

Find answers to questions asked by student like you

Show more Q&A

Q: A car hurtles off a cliff and crashes on the canyon floor below. Identify the system wherein the net...

A: The net momentum of the car and the earth system is zero. Hence, the system is Car-Earth system.

Q: Certain sunglasses use a polarizing material to reduce the intensity of light reflected from shiny s...

A: Since light waves are actually particles moving in wave form they are on both horizontal and vertica...

Q: The chin - up is one exercise that can be used tostrengthen the biceps muscle. This muscle can exert...

A: a)the work done is the product of force and distance\displacement in the direction of force.the expr...

Q: Why would it be a poor idea to have the back of your hand up against the outfield wall when you catc...

A: It would be poor idea to have the back of your hand up against the outfield wall when you catch a lo...

Q: A baseball is thrown from the outfield toward home plate.(a) True or False: Neglecting air resistanc...

A: Part A:

Q: A hummingbird hovers by exerting a downward forceon the air equal, on average, to its weight. By New...

A: Given,

Q: A block with mass m1 = 0.500 kg is released from rest on a frictionlesstrack at a distance h1 = 2.50...

A: The velocity of 0.5kg mass when it reaches the top of the tables is

Q: An air-filled parallel-plate capacitor with capacitance Co stores charge Qon plates separated by dis...

A: Part A

Q: A loaded ore car has a mass of 9.50 x 102 kg and rolls onrails with negligible friction. It starts f...

A: given:Mass of car = 9.5 X 102 kgInitial velocity of the car = 0Angle = 30oTime = 12 sFinal velocity ...