Acceleration Lab: page 33 Step 1: copy the chart below. Step 2: hold the ball 76 cm above the ground. (table height) Step 3: drop the ball record the time to reach the ground. Step 4: drop the ball from 152cm above the ground, record the time to reach the ground. Step 5: find the averages for both times. Distance Trial 1 Trial 2 Trial 3 Average 76 cm 152 cm
Page 32 1) Which time was shorter? Why? 2) Find the average speed for both distances? 3) The second drop was twice as far, why did it not take twice as long? 4) Find the acceleration of both averages. a = Vf – Vi t
Acceleration Page 35
How can an object have acceleration even though its speed is constant? Essential question: How can an object have acceleration even though its speed is constant?
Acceleration: A change in Velocity over time. a = velocity final – velocity initial = Δ V time t Has a value and a direction. + velocity increases with the direction of travel Going faster - velocity decreases with the direction of travel Going slower
Centripetal acceleration: If you move at a constant speed, but are moving in a circle, you are accelerating. The direction is always changing. Examples: moon, wheel, standing on earth, Ferris wheel.
Graphing Acceleration: Speed vs time graph Slope of the line equals acceleration Straight line would be constant acceleration On a distance vs time graph it will be a curved line.
Page 34 Explain why circular motion has acceleration even though the speed does not change? Identify the following as speeding up or slowing down: A) 5.7 m/s2 b) -29.8 m/s2 c) -2.43 m/s2 d) 9.8m/s2 3) What are the 3 ways a car can experience acceleration? 4) Graph the velocity vs time of a car that accelerates at 5m/s2 for a 5 seconds. (hint: calculate the speed at each second of time).