Name: Period: Date: / / Acceleration Worksheet Definitions: velocity: speed in a given direction acceleration: the rate at which the velocity is changing Acceleration Notes: 1. What are the three things you could do to accelerate? A. B. C. Equations: Check the MCAS formula sheet to identify these equations and variables. a avg = "v "t a = v f "v o t 2. What is the Unit? Write the correct unit and unit abbreviation for each of the following quantities. The first is done as an example. d Distance meter m t Time Δv Change of Velocity a Acceleration 3. Identifying Kinds of Quantities. For each of the following quantities, identify what kind of quantity it is. If the quantity is a velocity, mark it with an v, if it is a time, mark it t. If it is an acceleration, mark it a. If it is none of these, mark it N. The first is completed as an example. a _ 5.97 m/s 2 182 J 7.63x10 8 s 39.4 x10 24 s 1.66x10-26 m/s 38 m/s 2 3 x10 8 m/s 3.2 m/s 2 2.7 K 4. Getting the Formula Right. Velocity, displacement and time are related mathematically. Here are several formulas that relate the three quantities. Most of them are wrong! In each row, circle the formula that is correct, and cross out the rest. (Hint: For the first row, look at the Useful Information at the top of the page.) To find change in velocity: "v = a t "v = t a "v = a t To find acceleration: a = t "v a = "v t a = "v t To find time: t = "v a t = a "v t = a "v
5. Questions? Is there anything about this you d like cleared up? Problems: 6. A glider starts from rest and accelerates for 45 seconds. The final speed of the glider is 103 m/s. Find the average acceleration of the glider. Symbolic Formula Quantities Plugged In 7. A car (moving in a straight line) goes from rest to a speed of 20 m/s in 5 seconds. What is the car s acceleration? Symbolic Formula Quantities Plugged In 8. What is the final velocity of a skier who starts at rest and accelerates at a rate of 0.5 m/s 2 for 8 seconds? Symbolic Formula Quantities Plugged In 9. How long does it take a truck to increase its speed by 20 m/s if it has an acceleration of 2 m/s 2?
10. Complete the following table for a car accelerating from rest (constant acceleration) and answer the questions to the right: t (s) 0 v(m/s) 0 A. What is the car s initial speed? 1 2 3 6 B. What is the car s acceleration? 3 4 5 C. If the car were still accelerating 8 seconds after it started, how fast would it be moving? 6 Free-fall acceleration on Earth (aka: gravitational field strength): g earth = 9.81 m/s 2 " 10 m/s 2 d = 1 2 gt 2 " 5t 2 11. A flowerpot falls out a window, accelerating at 10 m/s 2. If it takes 3.6 seconds to reach the sidewalk below, what is the maximum speed of the pot? What far has the flowerpot fallen? Symbolic Formula Quantities Plugged In Symbolic Formula Quantities Plugged In
12. Objects which are dropped near the surface of the earth have an acceleration of around 10 m/s 2 down. Fill in the following chart: Time (sec) Velocity (m/s) 0 0 1 10 2 20 3 4 5 50 6 7 8 80 9 10 13. An object is dropped (from rest, on earth) and falls freely. After 4 seconds, what is its instantaneous speed? How far has it fallen? More Questions to Practice: 14. Which has a greater acceleration: a car that can go from 0 to 60 mph in 5 seconds or a car that can go from 0 to 60 mph in 10 seconds? Explain your answer. 15. What is the acceleration of a toy that starts at rest and reaches a final speed of 4 m/s in 10 seconds?
16. Which has a larger acceleration: a car that can go from rest to 10 mi/h in 5 seconds or a car that can go from 30 mi/h to 40 mi/h in 5 seconds? 17. A ball, which is rolling straight down a hill, has an acceleration of 4 m/s 2. If the ball starts from rest, what is the ball s velocity after 3 seconds? 18. A coconut falls freely* from a tree. It plummets for 2 seconds before hitting you on the head. How fast was the coconut going when it struck you? How many meters has the coconut traveled before it struck you? 19. A South African frog lands with a speed (just before hitting the ground) of 2.5 m/s. As it hits the ground it slows to a stop. It takes 0.25 seconds for the frog to come to a full stop. What is the average acceleration of the frog? 20. The highest speed ever achieved on a bicycle was 245 km/h. A. Use the factor conversion method to convert this to m/s. B. Suppose the average acceleration while slowing to a stop was 3 m/s 2. How much time does it take for the bicycle to stop?
21. We are moving in the negative direction. Our initial velocity is 40 m/s. Our final velocity is 10 m/s. This change in velocity takes 60 seconds. What was our average acceleration, in units of m/s 2? Show all four steps! 22. We are initially moving in the negative direction with a velocity of 20 m/s. We undergo an acceleration of 5 m/s 2. What is our velocity after 10 seconds? Do you think you should show all four steps? 23. We are initially moving in the negative direction with a velocity of 20 m/s. We undergo an acceleration of +5 m/s 2. Show all four steps as you calculate: A. time it takes to stop (reach v = 0 m/s) B. velocity after 6 s Question 24 is a challenge question; if you are thinking about taking honors chemistry, I expect you to try challenge questions! 24. Which would reach a higher final speed: a rock which is dropped on Earth and falls freely for 5 seconds or a rock which is dropped on the moon and falls freely for 5 seconds? Explain your answer.