Answer:
0.8s
Explanation:
Given parameters:
Height of shelf = 3m
Unknown:
Time it will take to hit the ground = ?
Solution:
To solve this problem, we use the expression below;
x = ut +
gt²
x is the height
u is the initial velocity = 0m/s
g is the acceleration due to gravity = 9.8m/s²
t is the time taken = ?
Now insert the parameters and solve for t;
3 = (0 x t) +(
x 9.8 x t²)
3 = 4.9t²
t² = 0.6
t = 0.8s
1.) potential energy
2.)potential and kinetic
3.)The roller coaster car has the most kinetic energy at point X i know this because the car is moving and kinetic energy has the power to move or change things therefore point X is when the roller coaster car has the most energy.
4.)potential energy
5.)kinetic energy
6.) potential and kinetic energy
Answer:
the final kinetic energy is 0.9eV
Explanation:
To find the kinetic energy of the electron just after the collision with hydrogen atoms you take into account that the energy of the electron in the hydrogen atoms are given by the expression:

you can assume that the shot electron excites the electron of the hydrogen atom to the first excited state, that is
![E_{n_2-n_1}=-13.6eV[\frac{1}{n_2^2}-\frac{1}{n_1^2}]\\\\E_{2-1}=-13.6eV[\frac{1}{2^2}-\frac{1}{1}]=-10.2eV](https://tex.z-dn.net/?f=E_%7Bn_2-n_1%7D%3D-13.6eV%5B%5Cfrac%7B1%7D%7Bn_2%5E2%7D-%5Cfrac%7B1%7D%7Bn_1%5E2%7D%5D%5C%5C%5C%5CE_%7B2-1%7D%3D-13.6eV%5B%5Cfrac%7B1%7D%7B2%5E2%7D-%5Cfrac%7B1%7D%7B1%7D%5D%3D-10.2eV)
-10.2eV is the energy that the shot electron losses in the excitation of the electron of the hydrogen atom. Hence, the final kinetic energy of the shot electron after it has given -10.2eV of its energy is:

Answer:
2 x 10^20 N
Explanation:
Me = 5.98 x 10^24 kg
Mm = 7.36 x 10^22 kg
r = 3.82 x 10^5 km = 3.82 x 10^8 m
The gravitational force between earth and moon is
F = G Me x Mm / r^2
F = (6.67 x 10^-11 x 5.98 x 10^24 x 7.36 x 10^22) / (3.82 x 10^8 x 3.82 x 10^8)
F = 2 x 10^20 N