How much work must be done on a 24-kg shopping cart to increase its speed
1 answer:
Answer:
The work done by the shopping cart is 180 J
Explanation:
We have,
Mass of a shopping cart is 24 kg
Initial speed of cart is 1 m/s
Final speed of a cart is 4 m/s
It is required to find the work done by the shopping cart. The work done by an object is also equal to the change in its kinetic energy as per work -energy theorem. It means,
m = 24 kg
u = 1 m/s and v = 4 m/s
So, the work done by the shopping cart is 180 J.
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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