7. When an object undergoes uniform circular motion. the direction of the (K)acceleration is: directed tangent to the circle directed toward the centre of the circle changing depending on its position in the circle directed outward from the centre of the circle opposite to the direction of centripetal force sense ------- 8.A car travels with a constant speed around a curve in the road. The curve is banked. Which of the following forces is in the direction of the net force on the car? (K) the x-component of the force of gravity the frictional force the x-component of the normal force the force of gravity the centrifugal force sense 9. A spring with a force constant of 150.0 N/m was stretched 5.7 cm. The work done to stretch the spring was (K) a. 0.24 J 0. 860 J b. 8.6 J e. 2400 J c. 430 J 10.Ifthe mass of a car is tripled and its speed is doubled. then the kinetic energy changes by a factor of: (K) a. 0.6? d. 12 b. 1.5 e. 18 c. 6 11.|f done long enough, rubbing two sticks together can produce enough heat to start a re. If 100.0 J of thermal energy is required to start the fire and the average frictional force between the sticks is 20.0 N, the distance the sticks must slide past one other is: (K) a. 2.00m d. 100.0 m b. 5.00 m e. 2.00 x103 m c. 10.0m 12. To catch a water-filled balloon without breaking it, people allow their hands to move with the balloon upon catching it. This works because: (K) a. the balloons momentum changes more slowly there is less force applied there is less impulse two ofA, B, and C all of A, B, and C sees 13. Two identical spheres of mass 1.0 kg each carry a charge of 1.0 C. In comparing the electric and gravitational forces between the spheres, it can be concluded that: (K) USCA ACADEMY SPH4U FINAL EXAM a. FE is greater than Fg b. F9 is greater than FE c. the two forces are equal d. the forces cannot be compared without knowing if the signs of the charges are the same or opposite the forces cannot be compared without knowing the distance between the spheres FD