I think the correct answer would be that because electromagnets are powerful and can be turned off and on anytime. Electromagnet is a magnet in which the magnetic field is made by the electric current that is induced to the system.

5 0

3 years ago

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In the 2008 Olympics, Jamaican sprinter Usain Bolt shocked the world as he ran the 100-meter dash in 9.69 seconds. Determine Usa

-Dominant- [34]

Answer:

His average speed was 10.3199 m/s.

Explanation:

4 0

3 years ago

Jeff is a landscaping contractor and lifts a rock weighing 600 pounds by wedging a board under the rock. Jeff weighs 150 pounds

jonny [76]

Answer: 4

The mechanical advantage is the ratio of the force exerted by the object to the force applied to do work on it.

Here, Jeff tried to lift a rock weighing 600 pounds by wedging board under the rock. Jeff who weighs 150 pounds uses all his weight to exert force on lever and lift rock.

Mechanical advantage, $M.A.=\frac{weight\hspace{1mm}of\hspace{1 mm}rock}{weight\hspace{1mm}of\hspace{1 mm}Jeff}=\frac{600 pounds}{150 pounds}=4.$

Therefore, the mechanical advantage that lever provided to Jeff in lifting rock is 4.

6 0

2 years ago

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