Answer:
Explanation:
Given that,
Mass of sledge hammer;
Mh =2.26 kg
Hammer speed;
Vh = 64.4 m/s
The expression fot the kinetic energy of the hammer is,
K.E(hammer) = ½Mh•Vh²
K.E(hammer) = ½ × 2.26 × 64.4²
K.E ( hammer) = 4686.52 J
If one forth of the kinetic energy is converted into internal energy, then
ΔU = ¼ × K.E(hammer)
∆U = ¼ × 4686.52
∆U = 1171.63 J
Thus, the increase in total internal energy will be 1171.63 J.
The rock will continue to travel in a straight line with a constant velocity for ever... The reason is, once it leaves your hand there is no force acting on the rock, so it will just continue to move in a natural motion which is constant velocity.
Answer:
-35 m/s
Explanation:
Momentum is conserved.
Momentum before firing = momentum after firing
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
Before the bullet is fired, the bullet and rifle have no velocity, so u₁ and u₂ are 0.
0 = m₁v₁ + m₂v₂
Given m₁ = 0.7 kg, v₁ = 350 m/s, and m₂ = 7 kg:
0 = (0.7 kg) (350 m/s) + (7 kg) v
v = -35 m/s
The rifle recoils at 35 m/s in the opposite direction.
When pushing the body it is necessary to break the frictional force generated by the floor. Once this frictional force is overcome, the body will begin to move. Ideally, if a constant velocity is maintained or close to this value, the acceleration that will be exerted will tend to be zero and therefore, by Newton's second law the value of the Force will also tend to minimum values.
Remember that this law tells us that
Therefore the best strategy is A. keep pushing the box forward at a steady speed
