A 17 kg child descends a slide 3.5 m high and reaches the bottom with a speed of 6.0 m/s. How much work was done by friction as the child goes down the slide?
a 100kg person slides down a 50m slide and reaches the bottom with a speed of 22m/s. how much thermal energy due to friction was generated in the process?
To find the work done by friction as the child goes down the slide, we can use the work-energy principle. According to this principle, the work done on an object is equal to the change in its kinetic energy. In this case, the work done by friction will be equal to the change in the child's kinetic energy as they go down the slide.
First, let's find the initial potential energy of the child at the top of the slide. The potential energy is given by the equation PE = mgh, where m is the mass of the child, g is the acceleration due to gravity (approximately 9.8 m/s^2), and h is the height of the slide.
PE = 17 kg x 9.8 m/s^2 x 3.5 m
PE = 588.7 J
Next, let's find the final kinetic energy of the child at the bottom of the slide. The kinetic energy is given by the equation KE = 1/2mv^2, where m is the mass of the child and v is the speed of the child at the bottom of the slide.
KE = 1/2 x 17 kg x (6.0 m/s)^2
KE = 306 J
The change in kinetic energy (ΔKE) is given by the equation ΔKE = KE2 - KE1, where KE2 is the final kinetic energy and KE1 is the initial kinetic energy (which is zero in this case since the child starts from rest).
ΔKE = 306 J - 0 J
ΔKE = 306 J
Therefore, the work done by friction is equal to the change in kinetic energy, which is 306 J.