Question

A ball is thrown upward with an initial speed of 50 m/s. (a) What will be its velocity 3 seconds after being thrown? (b) What will be its acceleration 3 seconds after being thrown? (c) How far above the ground will it be 3 seconds after being thrown? (d) What will be the velocity 5 seconds after the ball is thrown? (e) What will be the acceleration 5 seconds after the ball is thrown? (f) What will be the velocity 7 seconds after the ball is thrown?

15. You watch a feather falling with a constant speed. Is the feather in equilibrium? Explain.

16. Can two cars with equal speeds and have different velocities? Explain.

17. A car traveling 20 km/h skids 10 m to a stop with its brakes locked. How far will the same car skid with locked brakes when traveling 60 km/h?

18. In order to loosen a certain lug nut, a force of 100 N is applied at the end of a 30 cm (0.30 m) long wrench perpendicular to its length. (a) What is the torque that must be exerted to loosen the nut? (b)To achieve the same torque, what force must be applied at the end of a wrench that is 10 cm (0.10 m) long?

19. Robert’s bicycle has wheels with a circumference of 2 m. (a) If the wheels make 150 rotations in one minute, what is the linear speed of Robert’s bicycle? (b) Janet’s bicycle has wheels with a circumference of 1 m. In order for Janet’s bicycle to have the same linear speed found in part (a), how many revolutions per minute must the wheels make? 20.

Answer 1