Uniform Motion
Non-Uniform Motion
Work
Ep and Ek
Efficiency and ME
100
The main difference between a scalar and a vector is that a vector also shows ___________.
Direction.
100
A student on a bicycle started from a full stop and reached a velocity of 8.75 m/s in 3.8 s. What was his average acceleration?
2.3m/s2?
100
What 3 conditions must be met for there to be work done on an object?
1. Object must move
2. Force must be applied to move object
3. Direction of force and distance must be be the SAME
100
A book is lifted onto a shelf that is 1.57 m above the ground. Its gravitational potential energy on the shelf is 45.46 J. What is the mass of the book?
m= 2.95 kg
100
A skateboarder rolls down a ramp. At the bottom, she has a speed of 6.73 m/s. If her mass is 50 kg, determine the height of the top of the ramp above the bottom, assuming energy is conserved.
Ek = Ep **All energy is conserved so 100% of Ek turns into Ep and vice versa.
Ek = 1132. 3225 J = Ep
h= 2.3m
200
Alex walks 1.4 km west from the school and then walks 0.45 km east. What is his displacement?
-1.4km + 0.45km =-0.95 km [W]
200
A car is initially travelling at a velocity of 4.2 m/s [W]. If the car accelerates at a rate of 0.86 m/s2, how long will it take the car to reach a velocity of 9.6 m/s [W]?
6.3s
200
You exert a force of 25 N on your textbook while lifting it a height of 1.4 m to put it on a shelf. How much work did you do on your textbook?
35J
200
A car with a mass of 1500 kg is moving at a speed of 14 m/s. What is the kinetic energy of the car?
1.5 x 105 J
200
A kerosene lantern uses 984 J of chemical potential energy and produces 75 J of light energy. How efficient is the lantern in transforming chemical potential energy into light?
7.6%
300
An object travels a distance of 10.0 m in 4.6 s. What is the average speed of the object?
2.2m/s
300
What does the slope of a distance time graph tell you? What does the slope of a displacement time graph tell you?
Find the acceleration of this graph between 1-5s. What happens after 5s?
Speed. Velocity.
a= 5.0 m/s [fwd]
no change in position - at rest as v=0m/s
300
Calculate the area under the curve. What does this represent?
36 Nm. Area under the curve is the work done on the object.
300
You are ziplining at an adventure park and have a mass of 62.0kg. You begin on a platform that is 320cm above the ground. By the time you reach the end of the zipline, you are moving at 5.1m/s.
a) What is the total energy of the system?
b) How efficient is the zipline?
Ep= 1946.304 J
Ek= 806.310 J
ME= 2752.614 J --> 2.8 x 103J
Efficiency= 41%