Question 28

If your actual mechanical advantage is 10 J and the theoretical is 40 J, what is your percent efficiency? Hint: % Efficiency = (Actual MA/Ideal MA) * 100

a
400%
b
0.25%
c
25%
d
4%
Question 29
A lever has a mechanical advantage of 4. If you apply a force to the machine with a mass of 4 kg, at an acceleration of 2 m/s/s, what is the output force created by the lever? Hint: Use the equation Fo=MA*Fi.

a
0.5 N
b
0.5 J
c
32 N
d
32 J
Question 30
If an object is in free fall in the absence of air resistance, what is the only force acting on the object?

a
acceleration
b
terminal velocity
c
gravity
d
mass
Question 31
If an object has a mass of 20 kg on a planet with a force of gravity of 4 m/s2. What is the object's weight?

**Remember** W=mg

a
200 N
b
80 N
c
5 N
d
0.2 N
Question 32
The strength of gravity between two objects depends on:

a
Weight of the objects and distance between the two objects
b
The volume of the object and the weight of the objects
c
The Mass of the objects and the distance between the two objects
d
Mass of the objects and the volume of the objects

1 answer

Here are the answers to your questions:

Question 28
% Efficiency = (Actual MA / Ideal MA) * 100
% Efficiency = (10 J / 40 J) * 100 = 25%
Answer: c) 25%

Question 29
Output Force (Fo) = Mechanical Advantage (MA) * Input Force (Fi)
Given: MA = 4 and Fi = mass * acceleration = 4 kg * 2 m/s² = 8 N
So, Fo = 4 * 8 N = 32 N
Answer: c) 32 N

Question 30
If an object is in free fall in the absence of air resistance, the only force acting on it is:
Answer: c) gravity

Question 31
Weight (W) = mass (m) * gravity (g)
W = 20 kg * 4 m/s² = 80 N
Answer: b) 80 N

Question 32
The strength of gravity between two objects depends on:
Answer: c) The Mass of the objects and the distance between the two objects