thank you so much to the people who answered last time.
im not looking for the answers, more of an explanation of how to do it, so here is a few more
1]Brittany is changing the tire of her car on a steep hill 20.0 m high. she trips and drops the 10.0 kg spare tire, which rolls down the hill with an initial speed of 2.00 m/s. what is the speed of the tire at the top of the next hill, which is 5.00 m higher(ignore the effects of rotation KE and friction)
2] a mexican jumping bean jumps with the aid of a small worm that lives inside the bean A) if a bean of mass 2.0 g jumps 1.0 cm from your hand into the air, how much potential energy has it gained in reaching its highest point? B) what is its speed as the bean lands back in the palm of your hand?
3] a 500 kg pig is standing at the top of a muddy hill on a rainy day. the hill is 100.0 m long with a vertical drop of 30.0 m. the pig slips ad begins to slide down the hill. what is the pigs speed at the bottom of the hill. use the law of conservation of energy.A few more physics problems i dont get...?These are all energy balance problems.
Total Energy = Kinetic Energy + Potential Energy
TE = KE + PE
TE = 0.5 mass * velocity^2 + Mass * gravity * height
TE = 0.5MV^2 + MGH
TE = 0.5MV^2 + M*9.8 m/s^2 * H
That is all you need to work these problems.
#1Total Energy at top of first hill
TE = 0.5 * 10 kg * (2.0m/s)^2 + 10 kg * 9.8 m/s^2 * 20 m
That is all the energy you have to work with ===%26gt; TE is the same at the top of the second hill.
TE(from above) = 0.5 * 10 kg * V^2 + 10kg * 9.8 m/s^2*(20+5) m
Solve for V
#2
You should comvert to kg, meters, m/s That gets you Joules which is what you will need for most of the problems you get. Might as well get in the habit. That makes your memorized value for gravity of 9.8 m/s^2 useful.
2g = 0.002 kg
1cm = 0.01 m
TE = PE = 0.002 kg * 9.8m/s^2 * 0.01 m
That is all the energy you have to work with. All that converts to KE when it get back to your hand.
KE = TE (from above) = 0.5*0.002 kg * V^2
Solve for V
#3
The slope does not matter. We are assuming frictionless ==%26gt;
PE at the top = KE at the bottom
You try it.
