Electric motors require electricity to move the motor parts and do work (like an electric fan).
Elecgric generators actually burn diesel fuel to spin a motor around and around and around to GENERATE, or MAKE, electricity that you can then use to power your fans and lights in your house.
D. Talc, fluorite, fingernail, streak plate, diamond
Explanation:
Given parameters:
Mass of the weight = 15kg
Height of bar lift = 0.25m
Number of times lifted = 15times
Unknown:
Total height the bar was lifted = ?
Force needed for the lift = ?
Work done = ?
Solution:
To solve this problem we need to understand that;
Work done = Force x distance
Work done = mass x acceleration due gravity x height
Work done = weight x height
a. Total height:
Total height = 0.25 x 15 = 3.75m
b. Force needed ;
Force needed = Weight of bar = mass x gravity
= 15 x 9.8 = 147N
So;
Force used for the 15 times = 15 x 147 = 2205N
c. Work done ;
Work done = weight x height = 2205 x 3.75 = 8268.75J
<h3>
Answer:</h3>
375 N
<h3>
Explanation:</h3>
Topic tested: Newton's Law of motion
The question is testing on the application of Newton's second Law of motion.
We are given;
- Mass of the football = 5 Kg
- Initial velocity of the football, Vf = 15 m/s
- Time taken to bring the ball to rest = 0.2 s
- Final velocity, Vo = 0 m/s ( since the ball went to rest)
We are required to determine the force exerted to bring it to rest.
- According to the Newton's second law of motion the resultant force and rate of change in momentum are directly proportion.
Thus;
Force = 375 N
Hence, the force exerted on the ball by the receiver was 375 N