1. Light bulbs produce useful energy in the form of light and waste energy in the form of heat. What kind of light bulb would you use to incubate eggs?
A) high-efficiency light bulbs because they produce more heat
B) High efficiency light bulbs because they produce more light
C) low efficiency light bulbs because they produce more heat
D) low efficiency light bulbs because they produce more light
2. A machine has an efficiency of 15%. If the energy input is 300 joules, how much useful energy is generated?
A) 285 joules
B) 45 joules
C) 255 joules
D) 20 joules
3. A process generates 250 watts of useful energy and 609 watts of waste energy. What is the efficiency of the process?
A) 29%
B) 71%
C) 2.4%
D) 42%
4. A wheel and axle on a bicycle are designed with an axle radius of 0.5 feet and a wheel radius of 2 feet. If a force of 200 pounds is applied to the axle, what is the maximum output force of the bike wheel?
A) 1200 lb
B) 200 lb
C) 50 lb
D) 800 lb
5) a crowbar is being used with an actual mechanical advantage of 8. If the input force is 400 Newton’s on the 0.3-meter-long end of the crowbar, what is the output force on the short end?
A) 120 N
B) 960 N
C) 50 N
D) 3200 N
pls help me
pls can someone help me
it’s still me
im just sad now
1. low efficiency, produces more heat
2. 45J
3. 29%
4. 59lb
5. 3200N
pls 😭
anybody?
no one is responding
sorry 50 not 59 for 4
1. To choose the appropriate light bulb to incubate eggs, we need to consider the purpose of incubation. Incubation requires maintaining a specific temperature for the eggs to hatch successfully. Since light bulbs produce useful energy in the form of light and waste energy in the form of heat, the best option would be to use low-efficiency light bulbs that produce more heat.
Thus, the correct answer is C) low-efficiency light bulbs because they produce more heat.
2. To calculate the amount of useful energy generated by a machine with an efficiency of 15%, we need to multiply the efficiency by the energy input.
Efficiency = (useful energy output / energy input) * 100%
Given that the efficiency is 15% and the energy input is 300 joules:
Useful energy generated = Efficiency * Energy input = 15% * 300 joules = 0.15 * 300 joules = 45 joules
Therefore, the correct answer is B) 45 joules.
3. Efficiency is calculated by dividing the useful energy by the total energy output (useful energy + waste energy) and multiplying by 100% to get the percentage.
Efficiency = (useful energy / total energy output) * 100%
Given that the process generates 250 watts of useful energy (output) and 609 watts of waste energy:
Total energy output = Useful energy + Waste energy = 250 watts + 609 watts = 859 watts
Efficiency = (250 watts / 859 watts) * 100% ≈ 29%
Thus, the correct answer is A) 29%.
4. To determine the maximum output force of the bike wheel, we need to calculate the mechanical advantage of the wheel and axle system.
Mechanical Advantage = Radius of wheel / Radius of axle
Given that the axle radius is 0.5 feet and the wheel radius is 2 feet:
Mechanical Advantage = 2 feet / 0.5 feet = 4
Now, to find the maximum output force, we multiply the applied force on the axle by the mechanical advantage:
Maximum Output Force = Applied Force * Mechanical Advantage = 200 pounds * 4 = 800 pounds
Therefore, the correct answer is D) 800 lb.
5. To calculate the output force on the short end of the crowbar, we use the formula for calculating mechanical advantage:
Mechanical Advantage = Output Force / Input Force
Given that the input force is 400 Newtons and the actual mechanical advantage is 8:
Mechanical Advantage = Output Force / 400 Newtons = 8
Rearranging the equation, we can solve for the output force:
Output Force = Mechanical Advantage * Input Force = 8 * 400 Newtons = 3200 Newtons
Thus, the correct answer is D) 3200 N.