Answer:
Distance of closest approach, 
Explanation:
It is given that,
Charge on proton, 
Charge on alpha particle, 
Mass of proton, 
Mass of alpha particle, 
The distance of closest approach for two charged particle is given by :



So, their distance of closest approach, as measured between their centers
. Hence, this is the required solution.
A child climbing a ladder is transforming kinetic energy into potential energy.
Answer:
t = 7 sec.
Explanation:
As the car and the truck travel the same distance, assuming a constant acceleration, we can describe the movement of the truck and the car with these equations for this same displacement:
x(truck) = v*t (1)
x(car) = 
As the left sides of (1) and (2) are equal each other, the same must be true for the right sides:
v*t =
Solving for t, replacing v= 10.5 m/s and a= 3 m/s², we have:

⇒ t = 7 sec.
Answer:
5730 years
Explanation:
The half life of carbon-14 is 5730 years. If 50% of the carbon-14 remains, then exactly 1 half life has passed.
The half-life equation is:
A = A₀ (½)^(t / T)
where A is the remaining amount,
A₀ is the initial amount,
t is time,
and T is the half life.
In this case, A = ½ A₀ and T = 5730.
½ A₀ = A₀ (½)^(t / 5730)
½ = (½)^(t / 5730)
1 = t / 5730
t = 5730