Answer:
Explanation:
The total energy of an electron in an orbit consists of two components
1 ) Potential energy which is - ve because the field is attractive
2) Kinetic energy which represents moving electron having some velocity.
Kinetic is always positive.
3 ) In an orbit , The magnitude of potential energy is twice that of kinetic energy. So if -2E is the value of potential energy E wil be the value of kinetic energy.
4 ) Total energy will become some of potential energy and kinetic energy
-2E + E = -E
5 ) So total energy becomes equal to kinetic energy with only sign reversed.
In the given case total energy is -0.28 eV . Hence kinetic energy will be +0.28 eV.
When kinetic energy is calculated as +.28 eV , the potential energy will be
- 2 x .28 or - 0.56 eV .
Answer:
The force of gravity = 40 N
Explanation:
Given that,
The mass of a ball, m = 10 kg
The acceleration due to gravity on the surface of Mars, a = 4 m/s²
We need to find the force of gravity of the ball on Mars. The force of gravity on an object is given by :
F = mg
Substitute all the values,
F = 10 kg × 4 m/s²
F = 40 N
Hence, the correct option is (B).
Answer:
Iron is an essential element for production of blood cells in the body.
70% of iron in the body is composed in blood haemoglobin.
Answer:
0.45 m/s in the negative x-direction
Explanation:
From the law of conservation of momentum, the sum of initial momentum equals the sum of final momentum
Momentum, p=mv where m is the mass and v is the velocity
where 
is the common velocity, 
and 
are velocities of magnet moving in positive x-direction and magnet moving in negative x-direction respectively, 
and 
are masses of magnet moving in positive x-direction and magnet moving in negative x-direction respectively.
Substituting 125 g for and 85 g for , 7.33 m/s , -11.9 m/s for then
Therefore, the velocity of single unit is 0.45 m/s in the negative x-direction
