The correct answer is C) type of medium. Electromagnetic waves travel faster in solids than in liquids, and faster in liquids than in gases.
It's downward vector from the centre of apple in the direction to the centre of the Earth.
A) a mouse, to an order of magnitude = 0.1 m ( a tenth of a meter ) That would be a big mouse but the alternatives are 1 meter or one hundredth of a meter... so go with 1/10th
<span>b) Easy = 1 meter </span>
<span>c) two choices 10m or 100 m . Go with 100 m </span>
<span>d) Stretch it out , trunk tip to tail tip - call it 10 m </span>
<span>e) Your choice 100 m or 1000 m..... These are estimates. So long as you are within one order of magnitude you can't really be given wrong. So I'd say 100m</span>
Here we can use momentum conservation as in this type of collision there is no external force on it

now here we can say




now here we can say


now by coefficient of restitution
for elastic collision we know that e = 1


now by solving the two equation


also we know that

so final speed of the nail is 6.875 m/s