Answer:
<h3> 1.40625m/s²</h3>
Explanation:
Using the equation of motion expressed as v = u+gt where;
v is the final velocity of the ball
u is the initial velocity
g is the acceleration due to gravity
t is the time taken
Given
u = 9m/s
v = 0m/s
t = 6.4s
Required
acceleration due to gravity g
Since the rock is thrown up, g will be a negative value.
v = u+(-g)t
0 = 9-6.4g
-9 = -6.4g
6.4g = 9
divide both sides by 6.4
6.4g/6.4 = 9/6.4
g = 1.40625m/s²
Hence the acceleration due to gravity on the planet is 1.40625m/s²
1 kg ball can have more kinetic energy than a 100 kg ball as increase in velocity is having greater impact on K.E than increase in mass.
<u>Explanation</u>:
We know kinetic energy can be judged or calculated by two parameters only which is mass and velocity. As kinetic energy is directly proportional to the
and increase in velocity leads to greater effect on translational Kinetic Energy. Here formula of Kinetic Energy suggests that doubling the mass will double its K.E but doubling velocity will quadruple its velocity:

Better understood from numerical example as given:
If a man A having weight 50 kg run with speed 5 m/s and another man B having 100 kg weight run with 2.5 m / s. Which man will have more K.E?
This can be solved as follows:


It shows that man A will have more K.E.
Hence 1 kg ball can have more K.E than 100 kg ball by doubling velocity.
Answer:
8.1 x 10^13 electrons passed through the accelerator over 1.8 hours.
Explanation:
The total charge accumulated in 1.8 hours will be:
Total Charge = I x t = (-2.0 nC/s)(1.8 hrs)(3600 s/ 1 hr)
Total Charge = - 12960 nC = - 12.96 x 10^(-6) C
Since, the charge on one electron is e = - 1.6 x 10^(-19) C
Therefore, no. of electrons will be:
No. of electrons = Total Charge/Charge on one electron
No. of electrons = [- 12.96 x 10^(-6) C]/[- 1.6 x 10^(-19) C]
<u>No. of electrons = 8.1 x 10^13 electrons</u>
Proceed with caution before crossing