Answer:
3.True. The magnitude of momentum is the same
Explanation:
Let's propose the solution of the problem
The initial moment is
p₀ = m v
The final moment
= m (-v)
p₀ = -
Now we can review the claims
1. False. We see that the moment module is the same, but its direction changes
2. False. The impulse is a vector
3.True. The magnitude of momentum is the same
Answer:
The work done by Joel is greater than the work done by Jerry.
Explanation:
Let suppose that forces are parallel or antiparallel to the direction of motion. Given that Joel and Jerry exert constant forces on the object, the definition of work can be simplified as:
Where:
- Work, measured in joules.
- Force exerted on the object, measured in newtons.
- Travelled distance by the object, measured in meters.
During the first 10 minutes, the net work exerted on the object is zero. That is:
In exchange, the net work in the next 5 minutes is the work done by Joel on the object:
Hence, the work done by Joel is greater than the work done by Jerry.
Complete Question
An athlete at the gym holds a 3.0 kg steel ball in his hand. His arm is 70 cm long and has a mass of 4.0 kg. Assume, a bit unrealistically, that the athlete's arm is uniform.
What is the magnitude of the torque about his shoulder if he holds his arm straight out to his side, parallel to the floor? Include the torque due to the steel ball, as well as the torque due to the arm's weight.
Answer:
The torque is
Explanation:
From the question we are told that
The mass of the steel ball is
The length of arm is
The mass of the arm is
Given that the arm of the athlete is uniform them the distance from the shoulder to the center of gravity of the arm is mathematically represented as
=>
=>
Generally the magnitude of torque about the athlete shoulder is mathematically represented as
=>
=>