To answer the problem we would be using this formula which isE = hc/L where E is the energy, h is Planck's constant, c is the speed of light and L is the wavelength
L = hc/E = 4.136×10−15 eV·s (2.998x10^8 m/s)/10^4 eV
= 1.240x10^-10 m
= 1.240x10^-1 nm
Answer:
Work done by the force of friction is 305.96 joules.
Explanation:
It is given that,
Mass of the child, m = 21 kg
Height of the slide, h = 1.5 m
Speed of the child at the bottom, v = 0.51 m/s
Let W is the work done by the force of friction on the child. It can be calculated using the work energy theorem as :
W = -305.96 joules
So, the work done by the force of friction on the child is 305.96 joules. Hence, this is the required solution.
Answer:
313.6N
Explanation:
Given parameters;
Mass of the body = 50kg
Coefficient of friction = 0.64
Acceleration due to gravity = 9.81m/s²
Unknown:
Minimum force needed to move the body = ?
Solution:
To move this body, the minimum force must overcome the frictional force. So, the value of force that equals to that of the frictional force will set the body in motion.
Frictional force = Umg
U is the coefficient of friction
m is the mass
g is the acceleration due to gravity
Now insert the parameters and solve;
Frictional force = 0.64 x 50 x 9.8 = 313.6N
Answer:
v1 = v2
Explanation:
Given:
- The missing figure is (attached).
- The Magnetic Field B1 > B2
Find:
How does the speed v1 of the electron in region 1 compare with the speed v2 in region 2?
Solution:
- From Lorentz Law we know that the Force that acts on the charge particle is the cross product of Magnetic Field Vector ( B1 or B2 ) and the velocity vector (v1 or v1).
- From the attached figure related to this problem we see that the electron velocity or direction of motion is always parallel to the magnetic field B1&B2.
- The law of cross product for parallel vector is 0. Hence, the Lorentz force acting on the electron is also zero.
- Zero Force means no work is done on the particle by the magnetic field, thus, the change in kinetic energy also zero for conservation of energy to hold.
- The initial and final kinetic energies of the electron is same. Hence, we can conclude that v1 = v2.