33. State Newton's three laws of motion. 34. a) What is the weight of a 19 kg curling stone? b) What force if required to raise the curling stone without acceleration? 35. State the reaction force to each of the following action forces: a) the Earth attracts the moon with a force of 9.7x1024 N b) a cart pushes down on the floor with a force of 32 N c) the weight of a mass exerts a force of 0.75 N [down] on a string 36. Calculate the weight of a 54 kg robot on the surface of Venus where the gravitational field intensity is 8.9 N/kg . 37. The force of gravity experienced by an astronaut on Earth's surface is 750 N. What is the force of gravity on the same person at each of the following distances, in multiples of the Earth's radius, from the centre of Earth? a ) 3 b) 10 c) 22 38. An applied horizontal force of magnitude 9.1 N is needed to push a 2.8 kg lamp across a table at constant velocity. a) Determine the coefficient of kinetic friction between the lamp and the table. b) How would the coefficient of static friction compare with your answer in (a)? Why? 39. A 5.0 kg object made of one material is being pulled at constant velocity along a table made of another material. The coefficient of sliding friction between these two materials is 0.35. What is the magnitude of the force of friction? 40. State the law of conservation of energy. . A 2.0 kg mass is fired straight up with an initial velocity of 60.0 m/s. a) What is the kinetic energy of the mass when it is 20.0 m above the ground? b) What is the change in height when its speed changes from 50.0 m/s to 40.0 m/s? 42. A pendulum of length 1.0 m is raised 15 cm. What is the maximum speed it will reach at the bottom? 43. A horse pulls a cart a distance of 1.20 x 102 m and does 8.40 x 103 J of work. With what force was the horse pulling the cart? 44. Look at the diagram below. [ There is no friction or air resistance in (a) to (c).] 10.0 N 2.0 kg (a) If the block starts at rest, what is its kinetic energy after 2.0 s of travel? [Assume the applied force is continuous and constant. ] (b) How far does the block travel during the first 2 seconds? (c) The applied force is stopped at the end of the 2.0 s. How far will the block travel in 20.0 seconds, measured from start? [The total time is therefore 2.0 s + 18.0 s = 20.0 s] (d) If the block encounters friction at the end of the 20.0 s and stops in a total of 4.5 s, then what was the average coefficient of kinetic sliding friction for this block