Out of the choices given, igniting the gas-air mixture supplies the heat for the hot reservoir in a car's engine. The correct answer is C.
Answer:
When air resistance equals the weight of an object, the object has reached free fall.
Explanation:
- When an object has only force acting on it as gravity then, it experiences free fall.
- During free fall all the forces except gravity is balanced by one another.
- In the question, object's weight is balanced by air resistance so it is in the state of free fall.
- At the null point of free fall, object experiences weightlessness i.e. it feels like object is not attracted by any force.
Answer:
(B) tightly packed protons and neutrons
Explanation:
- Nucleus of any atom is the dense central part of any atom.
- It consists of two sub-atomic particle namely proton and neutron.
- These sub-atomic parts are tightly packed in nucleus which makes the nucleus dense .
- This dense nucleus is responsible for most of the mass of atom.
- The atomic mass for any atom is decided by sum of the mass of proton and neutron
Thus, correct answer is
(B) tightly packed protons and neutrons
Distance = velocity * time
1 hour and 15 minutes = 1.25 hours
25km/hr * 1.25 hours = 31.25km
