Answer:
F = 51.3°
Explanation:
The component of weight parallel to the inclined plane must be responsible for the rolling back motion of the car. Hence, the force required to be applied by the child must also be equal to that component of weight:

where,
W = Weight of Wagon = 150 N
θ = Angle of Inclinition = 20°
Therefore,

<u>F = 51.3°</u>
Answer:
Rod 1 has greater initial angular acceleration; The initial angular acceleration for rod 1 is greater than for rod 2.
Explanation:
For the rod 1 the angular acceleration is
Similarly, for rod 2

Now, the moment of inertia for rod 1 is
,
and the torque acting on it is (about the center of mass)

therefore, the angular acceleration of rod 1 is


Now, for rod 2 the moment of inertia is


and the torque acting is (about the center of mass)


therefore, the angular acceleration
is


We see here that

therefore

In other words , the initial angular acceleration for rod 1 is greater than for rod 2.
The 'Rite of Spring' was composed by Igor Stravinsky.
DIAMONDS are NOT rocks. Diamonds are minerals, rocks are made up of many different fragments of minerals.
Answer:
Microwave: Radiation
Water: Conduction, convection & radiation.
Explanation:
- When we heat a food using microwave then the water content of the food is only heated by the microwave.
- Microwaves make the molecules of water vibrate frequently with a frequency closer to the frequency of microwaves and this increases the kinetic energy of the molecules which produces heat in the water molecules this heat then propagates to the whole food by conduction and convection, but the heat enters the food only via radiation.
Now when the food item is kept into warm water then the molecules closer to the food heat the food by conduction through direct energy transfer by lattice vibrations and when they become cooler than the mass of water all around then due to density difference they settle down and their place is occupied by warmer molecules around in the fluid leading to convection.
Radiation of energy from a mass occurs continuously irrespective of the medium present there. So the heat of water also enters the food by radiation of energy from the water molecules.