So there are different ways this could be solved. I'll do try to explain it the way I was taught...
Simon is riding his bike at 12 km/hr relative to the sidewalk, away from where Keesha is.
Simon throws the ball at Keesha, at 5 km/hr.
Keesha sees the ball approaching her at (12-5) = 7 km/hr relative to the ground to her.
Therefore the answer is: 7 km/hr
Answer:
Explanation:
ASSUMING that block = sled AND that the rope is parallel to the slope.
The force acting parallel due to the weight is
13.6(9.81)sin35.5 = 77.475 N
The maximum friction force is
(0.45)13.6(9.81)cos35.5 = 48.877 N
If rope tension is T
77.475 - 48.877 < T < 77.475 + 48.877
28.6 N < T < 126 N
28.6 N will occur if the block is on the verge of sliding downhill
126 N will occur if the block is on the verge of sliding uphill
Could be any value between them.
The answer is C, a peer group.
I found the Hydrolic system, im not sire if its helpful or not. I could only find that one, sorry if it doesn't help but I hope it does ^-^