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1. [-/2 Points] DETAILS SERCP11 7.3.OP.005. ASK YOUR TEACHER PRACTICE ANOTHER A dentist's drill starts from rest and undergoes uniform angular acceleration for a period of 0.155 s until it turns at a rate of 2.65 x 104 rev/min. MY NOTES (a) What is the drill's angular acceleration (in rad/s?)? (Enter the magnitude.) rad/s² (b) What is the angle (in radians) through which the drill rotates during this period? (Enter the magnitude.) rad Need Help? 2. [0/4 Points] MY NOTES DETAILS ASK YOUR TEACHER PRACTICE ANOTHER Starting from rest, a rider pedals a bicycle such that the angular acceleration of the wheels is a constant 1.30 rad/s². The bicycle wheels are 37.5 cm in radius. Read It PREVIOUS ANSWERS (a) What is the magnitude of the bicycle's linear acceleration (in m/s²)? 0.4225 x How is the tangential acceleration of the wheel's edge related to the angular acceleration? Be careful with unit conversion. m/s2 SERCP117.3.OP.007. (b) What is the angular speed of the wheels (in rad/s) when the linear speed of the bicyclist reaches 10.6 m/s? 34.462 x How is the tangential velocity of the wheel's edge related to the angular velocity? Be careful with unit conversion, rad/s Need Help? (c) How many radians have the wheels turned through in that time? 456.81 x What constant acceleration formula relates final angular velocity to initial angular velocity, angular acceleration, and angular displacement? Can you use this to solve for the angular displacement? rad (d) How far (in m) has the bicycle traveled in that time? 148.4623 X How is the arc length (which is equal to the linear distance) related to the angular displacement? Be careful with unit conversion.m Read It
3. [-/2 Points] MY NOTES DETAILS SERCP11 7.3.P.014. ASK YOUR TEACHER An electric motor rotating a workshop grinding wheel at a rate of 1.41 x 10² rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 3.30 rad/s². (a) How long does it take for the grinding wheel to stop? Need Help? PRACTICE ANOTHER (b) Through how many radians has the wheel turned during the interval found in (a)? rad Read It
4. [-/2 Points] DETAILS SERCP117.4.OP.032. MY NOTES PRACTICE ANOTHER The figure below shows a roller-coaster car on a track. The car is fully loaded with passengers and has a total mass of 535 kg. At point A, the car is at the lowest point in a circular arc of radius r₁ = 11.0 m. At point B, the car is at the highest point of a circular arc of radius r₂ = 17.8 m. ASK YOUR TEACHER (a) If the car has a speed of 25.0 m/s at point A, what is the magnitude of the force (in N) of the track on the car at this point? N (b) What is the maximum speed (in m/s) the car can have at point B in order for the car to maintain contact with the track at all times (that is, so that it does not "jump" off the track)? m/s Need Help? Read It
5. [-/2 Points] DETAILS SERCP11 7.4.P.020. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Human centrifuges are used to train military pilots and astronauts in preparation for high-g maneuvers. A trained, fit person wearing a g-suit can withstand accelerations up to about 9g (88.2 m/s²) without losing consciousness. HINT (a) If a human centrifuge has a radius of 3.94 m, what angular speed (in rad/s) results in a centripetal acceleration of 9g? rad/s (b) What linear speed (in m/s) would a person in the centrifuge have at this acceleration? m/s Need Help? Read It 6. [-/3 Points] DETAILS Watch It SERCP11 7.5.P.034. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The International Space Station has a mass of 4.19 x 105 kg and orbits at a radius of 6.79 x 105 m from the center of Earth. Find the gravitational force exerted by Earth on the space station, the space station's gravitational potential energy, and the weight of an 83.0 kg astronaut living inside the station. HINT (a) the gravitational force (in N) exerted by Earth on the space station (Enter the magnitude.) (b) the space station's gravitational potential energy (in 3) (c) the weight (in N) of an 83.0 kg astronaut living inside the station N