Answer:
Explanation:
1. Impulse, I = F.t
The statement impulse is the product of Force and distance is false.
2. F = m g
Force necessary to lift the object depends on the mass of the object.
statement 2 is false.
3. Joule is equal to Newton times meter.
Statement 3 is false.
4. Work done to lift an object is correct statement.
Statement 4 is true.
5. Kinetic energy of an object is due to motion.
Statement 5 is false.
6. Stopping distance is directly proportional to the square of velocity.
If velocity is doubled, stopping distance is quadrupled.
Statement 6 is false.
Answer:
The last statement is false.
Explanation:
Photons (Electromagnetic radiation) are released when electrons drop from a higher energy lever to a lower energy level. Therefore the opposite insinuated by the last statement is wrong.
Answer:
ΔE = 37.8 x 10^9 J
Explanation:
The energy required will increased the potential energy and increase the kinetic energy.
As the altitude change is fairly small compared to the earth radius, we can ASSUME that the average gravity will be a good representative
Gravity acceleration at altitude would be 9.8(6400²/8000²) = 6.272 m/s²
G(avg) = (9.8 + 6.272)/2 = 8.036 m/s²
ΔPE = mG(avg)Δh = 1000(8.036)(8e6 - 6.4e6) = 12.857e9 J
The centripetal force at orbit must be equal to the gravity force
mv²/R = mg'
v²/8.0e6 = 6.272
v² = (6.272(8.0e6)) = 50.2e6 m²/s²
The maximum velocity when resting on earth at the equator is about 460 m/s.
The change in kinetic energy is
ΔKE = ½m(vf² - vi²)(1000)
ΔKE = ½(1000)(50.2e6 - 460²) = 25e9 J
Total energy increase is
25e9 + 12.857e9 = 37.8e9 J
Answer:
F = 2.69 10⁻³ m [ N]
Explanation:
This exercise asks to calculate the gravitational field of the Earth on the lunar surface, let's use the universal gravitation law
F = G m M / r²
where m is the mass of the body, M the mass of the Earth and r the distance between the Earth and the Moon
F = (G M / r²) m
F = (6.67 10⁻¹¹ 5.98 10²⁴ / (3.85 10⁸)² ) m
F = 2.69 10⁻³ m [ N]
This force is directed from the Moon towards the Earth, therefore it reduces the weight of the body
