<p>SPH 3U Unit #3 Review Questions</p><p>1. A race car has a mass of 710kg. It starts from rest and travels 40m in 3.0s. The car is uniformly accelerated during the entire time. What net force is applied to it? [6311.9N]</p><p>2. A 65kg swimmer jumps off a 10m tower. </p><p> a. Find the swimmer’s velocity when hitting the water. [14.01 m/s [down]] b. The swimmer comes to a stop 2m below the surface. Find the net force exerted by the water. [3189.55 N [up]]</p><p>3. The average rate of acceleration for a breaking car was -12.2 m/s2. If the car has a mass of 925kg, find the frictional force and state the direction. [11,285 N [backwards]]</p><p>4. If you use a horizontal force of 30.0N to slide a 12kg wooden crate across a floor at a constant velocity, what is the coefficient of friction between the crate and the floor? [0.25]</p><p>5. You are driving a 2500kg car at a constant speed of 14m/s along an icy, but straight and level road. While approaching a traffic light, it turns red. You slam on the brakes. Your wheels lock, the tires begin skidding and the car slides to a halt in a distance of 25m. What is the coefficient of sliding friction between your tires and the icy roadbed? [0.40]</p><p>6. Two boxes are side by side on a frictionless surface. Box X has a mass of 40kg and box Y has a mass of 20kg. If you push box X with a horizontal force of 48N: </p><p> a. Calculate the acceleration of both boxes. [0.8m/s2] b. Determine the force that box X applies to box Y. [16 N [forward]]</p><p>7. A physics book is moved once around the perimeter of a table of dimensions 1.0m by 2.0m.</p><p> a. If the book ends up at its final position, what is its displacement? [0] b. What is the distance traveled? [6 m]</p><p>8. Light from the sun reaches the Earth in 8.3min. The velocity of light is 3.0x108m/s. How far is the Earth from the sun? [1.49 x 1011 m]</p><p>9. You and a friend each drive 50km. You travel 90km/h, your friend at 95km/h. How long will your friend wait for you at the end of the trip? [0.03 hours or 108 seconds]</p><p>10. Ann is driving down a street at 55km/h. Suddenly a child runs into the street. It takes Ann 0.75s to react and apply the brakes. Her brakes then cause her to decelerate at 4m/s2. </p><p> a. How many meters will she have moved before she begins to slow down? [11.46m] b. If the child is 40m away when she first sees them, will she hit the child or stop in time? [the child will get hit ] SPH 3U</p><p>The following two questions refer to the graph below:</p><p>11. Using the dt graph, find the average velocity from 10 to 25s. [0.33 m/s [forward]]</p><p>12. Describe the motion of this object.</p><p>13. A driver approaches an intersection at a speed of 14m/s (50 km/s) when the light turns yellow. The driver applies the brakes to get the maximum stopping force without skidding. The car has a mass of 1500kg, and the force of limiting static friction between the tires and the road is 1.1x104N. Ignoring the driver’s reaction time, calculate:</p><p> a. The maximum deceleration of the car [7.33 m/s2] b. The minimum stopping time [1.91 s] c. The minimum stopping distance [13.37 m]</p><p>14. A 2.0kg object is moving across a table at constant speed of 2.0m/s against a force of friction of 6.0N. The applied force is suddenly increased by 1.0N. How fast will the object be moving after 3.0s? [3.5 m/s]</p><p>15. A skydiver, complete with a parachute, has a mass of 65kg. She opens her parachute when she reaches a velocity of 4.0m/s [down]. The parachute exerts an upward force of 650N. After the parachute opens, calculate:</p><p> a. the skydiver’s acceleration [0.19m/s2 [up]] b. her velocity after 2.0s [3.62 m/s [down]]</p>