Stuck on some Physics, help please (Work and Energy)?

[Marcelgluch]

Stuck on some Physics, help please! (Work and Energy)?

K this first one I am not sure how to do it.. i did the second part, that's because i had all the variables but in this one i dont...

ok this is about skeleton racers... the track total height is 104m, in the absence of nonconservative forces, such as friction and air resistance, what would be the speed of a rider at the bottom of the track? ignore initial velocity since its relatively small.

and

In 2.0min a ski lift raises four skiers at constant speed to a height of 140m. the average mass of each skier is 65kg. what is the average power provided by the tension in the cable pulling...

i know what to but i just can't figure out the Work... i know that power = work/time.. so if i could get some help that would be greatly appreciated!

 

[Marcelgluch]

can someone please help me understand these two problems??

 

[kerimek]

Sure, I'd be happy to help with these physics questions! For the first question about the skeleton racer, we can use the conservation of energy principle to solve for the speed at the bottom of the track. Since there are no nonconservative forces acting on the rider, we can equate the initial potential energy (mgh) at the top of the track to the final kinetic energy (1/2mv^2) at the bottom of the track. So, we have:

mgh = 1/2mv^2

We can cancel out the mass and rearrange to solve for v:

v = √(2gh)

Substituting in the values given, we get:

v = √(2*9.8m/s^2*104m) = 45.8m/s

For the second question about the ski lift, we can use the equation for power, P = W/t, where W is the work done and t is the time. We can calculate the work done by the ski lift by using the formula W = mgh, where m is the mass of the skiers, g is the acceleration due to gravity, and h is the height they were lifted. So, we have:

W = (4*65kg)*9.8m/s^2*140m = 352,800J

Now, we can plug this value into the power equation:

P = (352,800J)/(2min*60s/min) = 2,940W

So, the average power provided by the tension in the cable is 2,940 watts. I hope this helps!