frequency=4Hz
wavelength=5m
amplitude=1/2×2=1m
period=1/frequency
1/4=0.25seconds.
velocity=wavelength×frequency
=5×4
=20m/s
The ball should take twice as long to return to its original position as it took to reach its maximum height, so it should return to its original position at 
.
Answer:Wrap more turns of wire around the nail.
Explanation:The power of an electromagnet is directly proportional to the amount of electricity passing through that electromagnet.
Now,if they increase the number of rounds of the copper coil,the electricity conducting surface amount will also increase.
And that's why the electricity passing through that electromagnet will increase along with the electromagnetic power of that electromagnet.
• Increasing the battery voltage :
If they increase the battery voltage,the electricity which is passing through that electromagnet will also increase in amount .
And as discussed previously,the increasing amount of electricity will also increase the electromagnetic abilities of the electromagnet.
