Question 1: A 200W electric motor EM shown in the figure below is used to pull a mass m = 20kg to a height h = 5m. How long does it take to motor to do this? 2 seconds 2.5 seconds 3.5 seconds 5 seconds 7.5 seconds Question 2: Two objects of masses 10kg and 20kg have velocities v1 = 20m/s and v2 = 10m/s, on a collision course, as shown below. If 1500J of kinetic energy is lost in the plastic collision and the objects move on a frictionless surface, what is the momentum of the two objects after the plastic collision? 100 kg m/s 150 kg m/s 200 kg m/s 250 kg m/s 300 kg m/s Question 3: The momentum of an object is given by p(t) = 2t2 + 5t. What is the force acting on the object at t = 1s? 5 Newtons 7 Newtons 9 Newtons 10 Newtons 14 Newtons Question 4: A flat metallic piece of uniform density has a shape and dimensions shown below. A circle of 5cm diameter is cut out of a 100 cm2 square. The center of mass for the piece of metal is located at: x = 6.51cm and y = 5cm x = 5.61cm and y = 5cm x = 5cm and y = 5cm x = 5cm and y = 5.61cm x = 5cm and y = 6.51cm Question 5: A rod of length l = 1m has a mass density that changes with position x, ρ(x) = x + 1. The center of mass of the rod is at: x = 1/3 m x = 4/9 m x = 1/2 m x = 5/9 m x = 2/3 m Question 6: A rigid board of mass M and moment of inertia I is free to rotate about a hinge and is released from rest when it is in a horizontal position as shown below. What is the angular acceleration if four forces, all of magnitude F, are applied to the bar? 4Fd/I 4FI/d Fd/4I 4d/FI 4F/I Question 7: A cylinder with moment of inertia I = 10 kg·m2 is free to rotate about its symmetry axis. The cylinder starts from rest at time t = 0 seconds and accelerates with an angular acceleration of 0.2 rad/s2. What is the cylinder's angular momentum after t = 10s? L = 10 kg m2/s L = 20 kg m2/s L = 25 kg m2/s L = 35 kg m2/s L = 40 kg m2/s Press the Submit button to see the results.