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
4%
b
0.25%
c
400%
d
25%
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
32 N
b
32 J
c
0.5 N
d
0.5 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
mass
b
acceleration
c
terminal velocity
d
gravity
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
80 N
b
0.2 N
c
200 N
d
5 N
Question 32
The strength of gravity between two objects depends on:

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

1 answer

Here are the answers to your questions:

Question 28: To find the percent efficiency, you can use the formula: % Efficiency = (Actual MA / Ideal MA) * 100 = (10 J / 40 J) * 100 = 0.25 * 100 = 25%

Answer: d) 25%

Question 29: Using the equation \( F_o = MA \cdot F_i \), where MA (mechanical advantage) is 4 and \( F_i \) (input force) is determined by \( F = m \cdot a \). First, find the input force: \( F_i = m \cdot a = 4 \text{ kg} \cdot 2 \text{ m/s}^2 = 8 \text{ N} \).

Now substitute into the equation: \( F_o = 4 \cdot 8 = 32 \text{ N} \).

Answer: a) 32 N

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

Answer: d) gravity

Question 31: To find the weight of the object, use the formula \( W = mg \). Here, \( m = 20 \text{ kg} \) and \( g = 4 \text{ m/s}^2 \): \( W = 20 \text{ kg} \cdot 4 \text{ m/s}^2 = 80 \text{ N} \).

Answer: a) 80 N

Question 32: The strength of gravity between two objects depends on the mass of the objects and the distance between them.

Answer: a) The Mass of the objects and the distance between the two objects