When the iron bar is placed within the coils of a solenoid it then becomes a magnet.
Answer:
Part a: When the road is level, the minimum stopping sight distance is 563.36 ft.
Part b: When the road has a maximum grade of 4%, the minimum stopping sight distance is 528.19 ft.
Explanation:
Part a
When Road is Level
The stopping sight distance is given as

Here
- SSD is the stopping sight distance which is to be calculated.
- u is the speed which is given as 60 mi/hr
- t is the perception-reaction time given as 2.5 sec.
- a/g is the ratio of deceleration of the body w.r.t gravitational acceleration, it is estimated as 0.35.
- G is the grade of the road, which is this case is 0 as the road is level
Substituting values

So the minimum stopping sight distance is 563.36 ft.
Part b
When Road has a maximum grade of 4%
The stopping sight distance is given as

Here
- SSD is the stopping sight distance which is to be calculated.
- u is the speed which is given as 60 mi/hr
- t is the perception-reaction time given as 2.5 sec.
- a/g is the ratio of deceleration of the body w.r.t gravitational acceleration, it is estimated as 0.35.
- G is the grade of the road, which is given as 4% now this can be either downgrade or upgrade
For upgrade of 4%, Substituting values

<em>So the minimum stopping sight distance for a road with 4% upgrade is 528.19 ft.</em>
For downgrade of 4%, Substituting values

<em>So the minimum stopping sight distance for a road with 4% downgrade is 607.59 ft.</em>
As the minimum distance is required for the 4% grade road, so the solution is 528.19 ft.
<span>Slowing an
object down is not a means of accelerating it. It actually decelerates the
motion of an object. Speeding it up, changing its direction and applying
balanced forces accelerate an object. In order for an object to accelerate, a force
must be applied. It follows Newton’s second law of motion where it states that
a body at rest remains at rest unless a force is acted upon it. When you move
an object, you are exerting a force onto it. By exerting a force on the object,
you are actually displacing it from its initial position. You cannot apply
force to the object without altering its position. Keep in mind that when you
exert work, you are exerting energy too. </span>
Answer:
b) Gravity
Explanation:
Gravity acts all of the time, when you apply force to a projectile it has to be more than the forces of the gravity and air resistance together so the projectile can move, when the rock is at the top of its trajectory the force that you applied at the beginning is getting lost, so the other forces (air resistance and gravity) make the rock fall to the floor.
F = force applied to lift the box = weight of the box = 88 N
P = power produced while lifting the box upward = 72 Watt
v = speed of the box = ?
Speed of the box is given as
v = 
inserting the values
v = 
v = 0.82 ms⁻¹