Answer:
The wheelbarrow's wheel and axle help the wheelbarrow to move without friction thus making it easier to push or pull. That's why it will be easier to lift a load in wheel barrow of the load is transferred towards the wheel.
I'm not exactly sure but I'm thinking that it's the last one. Sorry if I'm wrong
Speed of wave is given as

Wavelength of the wave is given as

now from the formula of wave time period we can say




so it will have time period of T = 4 s
Answer:
Y
Explanation:
Y will produce the strongest magnetic force because the current intensity is medium and it has 50 turns in the wire. the number of turns will increase the force because the magnetic field will be more concentrated.
Have a great day :)