Complete Question
Suppose you hit a steel nail with a 0.500-kg hammer, initially moving at 15.0 m/s and brought to rest in 2.80 mm. How much is the nail compressed if it is 2.50 mm in diameter and 6.00-cm long.What Average force is excreted on the Nail
Answer:

Explanation:
From the question we are told that:
Mass 
Initial Velocity 
Distance 
Diameter 
Length 
Generally the equation for Force is mathematically given by



Explanation:
Given parameters:
Distance hopped = 84m
Displacement = 84m due east
Time = 7s
Unknown:
Speed of kangaroo = ?
Velocity of kangaroo = ?
Solution:
To solve this problem,
Speed =
=
= 12m/s
Velocity =
=
= 12m/s due east
We can solve the problem by using Ohm's law, which states that an Ohmic conductor the following relationship holds:

where

is the potential difference applied to the resistor
I is the current flowing through it
R is the resistance
In our problem, I=4.00 A and

, so the potential difference is
Explanation:
Answer is B.
B. It has a central nucleus composed of 29 protons and 35 neutrons,surrounded by an electron cloud containing 29 electrons.
I hope it's helpful!
A=F/m
a=(3000000)/(20000)
a=15 m/s^2