A bartender slides a mug of beer along a bar to a customer. The mug starts with a speed of 1.00 m/s, but by the time it reaches the customer's hand, it has slowed to 0.25 m/s. If the filled mug has a mass of 0.850 kg, how much work is done on the mug by kinetic friction as it slides along the bar to the customer?

Question

Julie Stevenson

Physics

14 May, 00:52

A bartender slides a mug of beer along a bar to a customer. The mug starts with a speed of 1.00 m/s, but by the time it reaches the customer's hand, it has slowed to 0.25 m/s. If the filled mug has a mass of 0.850 kg, how much work is done on the mug by kinetic friction as it slides along the bar to the customer?

+2

Answers (1)

Know the Answer?

Braedon Bolton · Answer 1

Initial velocity u = 1 m / s

final velocity v =.25 m / s

mass of the mug m =.85

initial kinetic energy

= 1/2 x. 85 x 1 x 1

=.425 J

final kinetic energy

= 1/2 x. 85 x. 25 x. 25

=.0265 J

Loss of kinetic energy

=.425 -.0265 J

=.3985 J

Work done by friction

= -.3985 J (loss of kinetic energy is due to negative work by friction)