Answer:
a) 3.43 m/s
Explanation:
Due to the law of conservation of momentum, the total momentum of the bullet - rifle system must be conserved.
The total momentum before the bullet is shot is zero, because they are both at rest, so:

Instead the total momentum of the system after the shot is:

where:
m = 0.006 kg is the mass of the bullet
M = 1.4 kg is the mass of the rifle
v = 800 m/s is the velocity of the bullet
V is the recoil velocity of the rifle
The total momentum is conserved, therefore we can write:

Which means:

Solving for V, we can find the recoil velocity of the rifle:

where the negative sign indicates that the velocity is opposite to direction of the bullet: so the recoil speed is
a) 3.43 m/s
Answer:
The door will move when the forces exerted by each individual becomes unbalanced.
Explanation:
The Door will only move when the forces exerted by each of the individual is unbalanced i.e. when the Torque is unbalanced
This is because there will only be a reaction or movement of an object when the applied force > resistant force acting on the object.
example : An object at rest will only move when the applied force is greater than the frictional forces acting on the object at rest.
Answer:
Because it has more mass
Explanation:
To understand this, think about the equation of kinetic energy
KE =
m 
Kinetic energy depends on both the velocity (v) as well as the mass (m).
Because a lorry is bigger and heavier than a car, it will have more mass. With more mass, at the same velocity the lorry with have more kinetic energy.
Answer:
1.a storm with a violent wind, in particular a tropical cyclone in the Caribbean.
2.The Eye of a Hurricane. The eye is the region at the center of the hurricane, which is roughly circular in shape and usually has calm weather.
3.Hurricanes form over the ocean, often beginning as a tropical wave—a low pressure area that moves through the moisture-rich tropics, possibly enhancing shower and thunderstorm activity.
4.When the surface water is warm, the storm sucks up heat energy from the water, just like a straw sucks up a liquid. This creates moisture in the air. If wind conditions are right, the storm becomes a hurricane. This heat energy is the fuel for the storm.
5.a rising of the sea as a result of atmospheric pressure changes and wind associated with a storm.
6.A hurricane dies down when it loses its energy source, which is usually warm water at the surface of the ocean.
7.Hurricane Katrina was so destructive because of a bunch of events that happened in just the right way. First, understand that Katrina was at one point a Category 5 storm and was predicted to hit New Orleans as a Category 4. It weakened to a Cat 3 and veered ever so slightly to the east, making the damage far less than it could have been.
Explanation:
hope this helps