Physics First Quiz #1



AP Advanced Forces Test: Funnel of Death_________________________Name Use g = 9.8 m/s2.Solve problems algebraically first, then plug in the numbers. Color code all force vectors: green for gravity, red for normal, orange for friction, and blue for a push or pull (including tension).1. Sam is in an elevator cab at rest a distance y = 75 m above the basement floor when the lifting winch suddenly fails. The counterweight has a mass mcw = 1200 kg, the elevator cab and its contents have a total mass mcab = 1400 kg. Emergency brake provides an upward force of FB = 1500 N on the elevator cab. No other forces act on the system.Use the three step program to find the acceleration of the elevator cab.952514605mcabmcwStep 1: Draw FBD’s. Include + arrow! Note: + direction needs to be consistent with acceleration. Making + down on one side means + is up on the other side.Step 2: Apply someone’s second law to each object…Step 3: Solve for a:mcwEmergency brake acts on cabmcabFor mcw:For mcab:0mcabmcwStep 1: Draw FBD’s. Include + arrow! Note: + direction needs to be consistent with acceleration. Making + down on one side means + is up on the other side.Step 2: Apply someone’s second law to each object…Step 3: Solve for a:mcwEmergency brake acts on cabmcabFor mcw:For mcab:How fast are Sam and the cab traveling when they slam into the basement floor? Assume vo = 0. 4298950834814m00m2. You are pushing horizontally on a wet, slippery glass mirror of mass m against a wall as shown, trying to hold it in place. The coefficient of static friction between the wall and the mirror is μs. Assume there is no frictional force between your hand and the mirror. Use the 3 step program to find the minimum force Fp that you must apply to keep the mirror from sliding down the wall, in terms of μs, m, and any necessary constants. 10795062230WallFpm MirrorHandStep 1: FBDStep 2:WallFpm MirrorHandStep 1: FBDStep 2:422275036195002736850153670Step 3: Solve for Fp00Step 3: Solve for Fp3. Ethan goes for a ride on the spinning, inverted “Funnel of Death.” The walls of the funnel are tilted inward at an angle of θ from the vertical as shown. The coefficient of static friction between him and the wall is μs. It’s all very funny until Sophia gets a hold of the controls and slows its rotational speed down until Ethan is just about to fall out. A) Let’s find the maximum period of rotation T of the funnel that will barely keep Ethan from falling out.45085013970θR00θRStep 1: Draw all the forces on Ethan in the sketch above. Then add the forces together graphically in this box, identifying θ. Step 2: (Apply in two different directions…)335597516256000Combine your two equations to eliminate FNStep 3: Solve for T.Is there a maximum value for θ for which no value of T will work to keep Ethan in the funnel? Find the maximum θ in terms of μs. ................
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