Hi there!
Initially, we have gravitational potential energy and kinetic energy. If we set the zero-line at H2 (12.0m), then the ball at the second building only has kinetic energy.
We also know there was work done on the ball by air resistance that decreased the ball's total energy.
Let's do a summation using the equations:
Our initial energy consists of both kinetic and potential energy (relative to the final height of the ball)
Our final energy, since we set the zero-line to be at H2, is just kinetic energy.
And:
The work done by air resistance is equal to the difference between the initial energy and the final energy of the soccer ball.
Therefore:
Solving for the work done by air resistance:
Answer:
So A we cant sadly do because we cant draw. B is going to be kinetic. Thats because static friction means it stays in one place, for kinetic it means moving. So it will be 0.05 as the coefficient of the friction. Sadly, I cannot calculate C. You will have to use trigonemetry but I cannot fit that big an explanation.
Answer to A: the free body diagram would be the ski things inclined with gravity, friction, and air resistance. I except you know which directions
Answer to B: Kinetic friction is the answer.
Answer to C: Find on own, I cannot write super big explanations - use trigonometry.
Answer:
D. power
Explanation:
kg represents mass
(m/v)² represents velocity squared
Then kg·m²/s² represents mass·velocity² = <em>kinetic energy</em> or <em>potential energy</em> or <em>work</em>.
kg·m²/s³ will be the <em>rate of doing work</em>, which is power
Answer:
786.6 N
Explanation:
mass of car, m = 912 kg
initial velocity of car, u = 31.5 m/s
final velocity of car, v = 24.6 m/ s
time, t = 8 s
Let a be the acceleration of the car
Use first equation of motion
v = u + a t
24.6 = 31.5 + a x 8
a = - 0.8625 m/s^2
Force, F = mass x acceleration
F = 912 x 0.8625
F = 786.6 N
Thus, the force on the car is 786.6 N.
