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

=> 
=> 
Answers:
a) -171.402 m/s
b) 17.49 s
c) 1700.99 m
Explanation:
We can solve this problem with the following equations:
(1)
(2)
(3)
Where:
is the bomb's final jeight
is the bomb'e initial height
is the bomb's initial vertical velocity, since the airplane was moving horizontally
is the time
is the acceleration due gravity
is the bomb's range
is the bomb's initial horizontal velocity
is the bomb's fina velocity
Knowing this, let's begin with the answers:
<h3>b) Time</h3>
With the conditions given above, equation (1) is now written as:
(4)
Isolating
:
(5)
(6)
(7)
<h3>a) Final velocity</h3>
Since
, equation (3) is written as:
(8)
(9)
(10) The negative sign ony indicates the direction is downwards
<h3>c) Range</h3>
Substituting (7) in (2):
(11)
(12)
Answer:
<h2>18150 J</h2>
Explanation:
The kinetic energy of the car can be found by using the formula

m is the Mass
v is the velocity
From the question we have

We have the final answer as
<h3>18150 J</h3>
Hope this helps you
<h2>
Average speed of transit train is 60 mph</h2>
Explanation:
Average speed of passenger train = 45 mph
Time taken from station A to station B for passenger train = 10:00 - 6:00 = 4 hours
Distance between station A to station B = 45 x 4 = 180 miles.
Time taken from station A to station B for transit train = 4 - 1 = 3 hours
Distance between station A to station B = Average speed of transit train x Time taken from station A to station B for transit train
180 = Average speed of transit train x 3
Average speed of transit train = 60 mph
Average speed of transit train is 60 mph