Answer:
The total momentum before and after collision is 72000 kg-m/s.
Explanation:
Given that,
Mass of car = 1200 kg
Velocity of car = 10 m/s
Mass of truck = 2000 kg
Velocity of truck = 30 m/s
Using conservation of momentum
The total momentum before the collision is equal to the total momentum after collision.

Where,
=mass of car
=velocity of car
=mass of truck
=velocity of truck
Put the value into the formula



Now, The total momentum before collision is



The total momentum after collision is



Hence, The total momentum before and after collision is 72000 kg-m/s.
Answer:
The electric force is 
Explanation:
From the question we are told that
The Bohr radius at ground state is 
The values of the distance between the proton and an electron 
The electric force is mathematically represented as

Where n and p are charges on a single electron and on a single proton which is mathematically represented as

and k is the coulomb's constant with a value

substituting values
![F = \frac{9*10^{9} * [(1.60*10^{-19} ]^2)}{(2.63 * 0.529 * 10^{-10})^2}](https://tex.z-dn.net/?f=F%20%3D%20%20%5Cfrac%7B9%2A10%5E%7B9%7D%20%2A%20%20%5B%281.60%2A10%5E%7B-19%7D%20%5D%5E2%29%7D%7B%282.63%20%2A%200.529%20%2A%2010%5E%7B-10%7D%29%5E2%7D)

100kg x bicycle speed = 1400 X 2
bicycle speed = 2800/ 100
bicycle speed = 28 m/s
Based on internet sources, <span>the basic formulas are: v^2/r = (at)^2/r = a ==> at^2 = r ==> t = sqrt(r/a).
</span>
<span>Assuming the missing units are mutually compatible, as in the following example, they don't need to be known. </span>
<span>Acceleration = 1.6 cramwells/s^2 </span>
<span>Radius = 150 cramwells </span>
<span>t = sqrt(150/1.6) = 9.68 s.
I hope this helps.</span>