Answer:
Planet will crash on to the Sun if the tangential velocity becomes zero and Rocket should be fired from Earth's orbit is at 30 m/s and in opposite direction to the Earth orbits the Sun
Explanation:
The orbital velocity of the Earth about the sun is 30 km/s. If we shoot a rocket with 30 km/s with respect to Earth in the opposite direction. Then the two velocity vectors cancel. The resultant velocity would be zero with respect to the Sun. resulting velocity is called as tangential velocity.
Planet will crash on to the Sun if the tangential velocity becomes zero and Rocket should be fired from Earth's orbit is at 30 m/s and in opposite direction to the Earth orbits the Sun
Answer:
The ratio of kinetic energies of 5 kg object to 20 kg object is 1:1.
Explanation:
Kinetic energy is defined as energy possessed by an object due to its motion.It is calculated by:

Kinetic energy of the 5 kg object.
Mass of object,m = 5 kg
Velocity of an object = v

Kinetic energy of the 20 kg object.
Mass of object,m' = 20 kg
Velocity of an object = v'

The ratio of the kinetic energy of the 5 kilogram object to the kinetic energy of the 20-kilogram object:

Given that, v = 2v'

The ratio of kinetic energies of 5 kg object to 20 kg object is 1:1.
Answer:
The coefficient of friction in the hall is 0.038
Explanation:
Given;
mass of the Parker, m = 73.2 kg
applied force on the parker, F = 123 N
frictional force, Fs = 27.4 N
the coefficient of friction in the hall = ?
frictional force is given by;
Fs = μN
Where;
μ is the coefficient of friction
N is normal reaction = mg
Fs = μmg
μ = Fs / mg
μ = (27.4) / (73.2 x 9.8)
μ = 0.038
Therefore, the coefficient of friction in the hall is 0.038
Total mechanical energy = kinetic energy + potential energy
E = KE + PE
E = ½mv² + mgh
E = ½(0.1 kg)(2 m/s)² + (0.1 kg)(9.8 m/s²)(1.5 m)
E = 0.2 J + 1.47 J
E = 1.67 J
The correct answer is C) towards the center of the circle.
Although the object is moving at a constant speed it is constantly accelerating due to the constant change in direction as it describes the circular path. This causes a constant change in velocity as velocity is a vector quantity.
For the object to maintain the circular path there has to be centripetal force acting on the object and this centripetal force is directed towards the center of the circle.