(d) When a = 4 m/s (towards the ground) w m(g-a) = 50 (10 - 4) = 500- 200 = 300 N oune %3D The rope will not break. The re The A ha Exercise 16.5 1. (a) State Newton's third law of motion. (b) Using examples, differentiate betweer action and reaction forces. 2. A driver jumps from a plane on an air cushion His speed is 24 m/s. The average force of the cushion on the body while he is being stopped is 9 400 N. If his mass is 70 kg, calculate the distance he will sink into the cushion. in 3. A man standing in a lift holds a spring balanc with a load of 5 kg suspended from it. What is the reading on the spring if the lift descending with an acceleration of 3.8 m/s? pplications of Newton's third w ome prastica situation

(II) At the instant a race began, a 65-kg sprinter exerted a force of 720 N on the starting block at a 22° angle with respect to the ground. (a) What was the horizontal acceleration of the sprinter? (b) If the force was exerted for 0.32 s,with what speed did the sprinter leave the starting block?

(II) Drag-race tires in contact with an asphalt surfacehave a very high coefficient of static friction. Assuming aconstant acceleration and no slipping of tires, estimatethe coefficient of static friction needed for a drag racer tocover 1.0 km in 12 s, starting from rest