Answer:
D. Newton's second law
Explanation:
Newton's second law of motion states that force of an object is a product of its mass and its acceleration.
Mathematically, F= ma where m is mass and a is acceleration
So from the statement above : The acceleration of an object is proportional to the force applied to it and inversely proportional to its mass , it can be seen from the formula variation as;
F= ma -----making a the subject of the formula
a= F/ m
a= 1/m * F --------- a is inversely related to m as you can see from 1/m but directly related to F hence;
Increase in mass with the same force applied causes the body to accelerate slower where as when force increases, the body accelerates faster.
Complete Question
The complete question is shown on the uploaded image
Answer:
The tension on the shank is 
Explanation:
From the question we are told that
The strain on the strain on the head is 
The contact area is
Looking at the first diagram
At 600 MPa of stress
The strain is 
At 450 MPa of stress
The strain is 
To find the stress at
we use the interpolation method

Substituting values



Generally the force on each head is mathematically represented as

Substituting values


Now the tension on the bolt shank is as a result of the force on the 6 head which is mathematically evaluated as



Answer:
Do neither of these things ( c )
Explanation:
For length contraction : Is calculated considering the observer moving at a speed that is relative the object at rest applying this formula
L = (l) 
where l = Measured distance from object at rest, L = contracted measured in relation to the observer , v = speed of clock , c = speed of light
you will do neither of these things because before you can make such decisions who have to view the object in this case yourself from a different frame from where you are currently are, if not your length and width will not change hence you can't make such conclusions/decisions .
Observer A is moving inside the train
so here observer A will not be able to see the change in position of train as he is standing in the same reference frame
So here as per observer A the train will remain at rest and its not moving at all
Observer B is standing on the platform so here it is a stationary reference frame which is outside the moving body
So here observer B will see the actual motion of train which is moving in forward direction away from the platform
Observer C is inside other train which is moving in opposite direction on parallel track. So as per observer C the train is coming nearer to him at faster speed then the actual speed because they are moving in opposite direction
So the distance between them will decrease at faster rate
Now as per Newton's II law
F = ma
Now if train apply the brakes the net force on it will be opposite to its motion
So we can say
- F = ma

so here acceleration negative will show that train will get slower and its distance with respect to us is now increasing with less rate
It is not affected by the gravity because the gravity will cause the weight of train and this weight is always counterbalanced by normal force on the train
So there is no effect on train motion