Question

1. An unknown mass (mı) on a rough horizontal surface is attached by a wire that passes over a massless, frictionless pulley to a 2.50kg mass (m2) as shown below. The bottom of the hanging mass is 1.50m above the floor. The system is released from rest at t-0s and the 2.50kg mass strikes the floor 0.82s later. The system is now returned to its initial position and a 1.20kg mass is placed on top of the block of mass mi. Released from rest, the 2.50kg mass now strikes the floor after 1.30s. (a) Determine the value of the mass (m. (b) Determine the coefficient of kinetic friction between the block of mass m1 and the rough horizontal surface A 750kg car travels at 90km/hr around a curve with a radius of 160m. (a) How fast is the car traveling in meters per second? (b) What should the banking angle of the curve be so that the only force between the pavement and tires of the car is the normal reaction force? 2. The radius of curvature of a loop-the-loop rollercoaster is 12.0m. At the top of the loop, the force that the seat exerts on a passenger of mass mis 0.4mg. Find the speed of the rollercoaster at the top of the loop. 3. An astronaut working on the International Space Station is trying to save time by pushing a damaged solar panel away into space. Assume that the astronaut's mass with her suit is 100kg and the panel's mass is 80kg. She is at rest with respect to the station when she pushes the panel away from the station at 0.3m/s relative to the station. What is her subsequent velocity relative to the station (for safety's sake let's assume that she has a long tether attaching her to the space station)? 4. Given that m1-4.0kg. The coefficient of static friction between the block and the incline is 0.4. (a) Find the range of possible values for mafor which the system will be in static equilibrium. (b) What is the frictional force on the 4.0kg block if m2-1kg? 5. A 2.0kg block hangs from a spring scale calibrated in newtons that is attached to the ceiling of an elevator. What does the balance read (in newtons) when (a) the elevator is moving up with a constant velocity of 30m/s; (b) the elevator is moving down with a constant velocity of 30m/s; (c) the elevator is ascending at 20m/s and gaining speed at a rate of 10m/s2? (d) From t-Os to t-2.0s, the elevator moves upward at 10m/s. Its velocity is then reduced uniformly to zero in the next 2.0s so that it is at rest at te4.0s. Describe the reading on the scale during the interval O<t<4.0s 6. A3 AS PA

Answer 1

mp Vaticas Fores ㄒ rm 2 frorn ef"(i)

2 1.21m 2 t0y) (m,tH 2)a no from, weseh 1.77(13-85 ナ1.2