Ch. 2 slides Turn-a-round.ppt

Graph 1 x Do A and B ever have the same speed? If so, at what time or times? Explain your answers. Velocity.ppt

Graph 2 x Do A and B ever have the same speed? If so, at what time or times? Explain your answers. Velocity.ppt

A Train Without Equations A train is moving at a steady 30 m/s. At t = 0 s, the engine passes a signal light at x = 10 m. Draw a velocity vs. time graph. Draw a position vs. time graph for the train. Without using any equations, find the position of the train at t = 1, 2, and 3 s. Velocity.ppt

Changing Position to Velocity x (m) 40 30 20 10 t (s) -10 1 2 3 4 5 Use the graph to find the velocity, then graph velocity vs. time. Your graph should be labeled and accurate with your numbers. Velocity.ppt

Changing Velocity to Position v (m/s) 40 30 20 10 t (s) 1 2 3 4 5 Using the graph (not equations), find the position at t = 1, 2, 3, 4, 5 s assuming at t = 0 s, x = 10 m. Then draw a position vs. time graph. Velocity.ppt

Position to acceleration graphs Plot velocity vs.time and acceleration vs. time for the following position vs. time graph. XVAvsT.ppt

Acceleration to position graphs Plot velocity vs.time and position vs. time with appropriate numerical scales for the following acceleration vs. time graph. Assume vo = 0 m/s, x0 = 0 m. XVAvsT.ppt

UFO The police in Roswell, NM are used to seeing strange things. One night an officer sees an object flying across the sky. The officer’s radar gun measures the velocity of the object and finds it obeys the equation v(t) = -20 + 10t2 m/s. If the object was at x = 20m at t = 0, derive the equations for x(t) and a(t). Plot x(t), v(t) and a(t) for t = 0 to 3 s. What is the largest acceleration recorded in g’s? What is the average acceleration from t = 0 to 3 s? What is the average velocity from t = 0 to 3 s? Challenge: what is the average position from t = 0 to 3 s? XVAvsT.ppt

Deer Problem 2.49 Suppose that you are driving down the road at a speed of 20 m/s and a deer stops in front of your car, frozen by your headlights. If the acceleration of the car while braking is 10 m/s2 and your reaction time is 0.5 s, what is the minimum distance you could have started away from the deer so that you don’t hit it? Set up a pictorial representation and solve using kinematics. acceleration.ppt

Rocket I A rocket starts from rest on the ground, and accelerates upwards at a constant acceleration of 20 m/s2 for 5 seconds, at which time the engine quits. In this problem, you can neglect air resistance, and take the acceleration due to gravity to be g = 10 m/s2. Find the maximum altitude (distance above the ground) the rocket reaches during its motion. acceleration.ppt

Catch Train You want to visit your friend in Seattle over Spring break. To save money, you decide to travel there by train. But you are late finishing your physics final, so you are late in arriving at the train station. You run as fast as you can, but just as you reach one end of the platform your train departs, 30 meters ahead of you down the platform. You can run at a maximum speed of 8 m/s and the train is accelerating at 1 m/s2. You can run along the platform for 50 meters before you reach a barrier. Sketch a position vs. time graph for the train. Sketch a position vs. time graph assuming you miss the train. Will you catch your train? acceleration.ppt

Rocket II Problem 2.56 A 1000 kg weather rocket is launched straight up. The rocket motor provides a constant acceleration for 16 seconds, then the motor stops. The rocket altitude 20 seconds after launch is 5100 meters. Sketch position vs. time, velocity vs. time, and acceleration vs. time for the rocket. What was the rocket’s acceleration during the first 16 seconds? What is the rocket’s speed as it passes through a cloud 5100 meters above the ground? acceleration.ppt

Dropped Ball Problem 2.57 A 5 kg lead ball is dropped into a lake from a diving board 5.0 meters above the water. It hits the water with a certain velocity and then sinks to the bottom with this same constant velocity, reaching the bottom 3.0 seconds after it is dropped. a) Sketch position vs. time, velocity vs. time and acceleration vs. time graphs (don't worry about numbers right now, just get the correct shape) b) How deep is the lake? acceleration.ppt