Answer:
Explanation:
mass, m = 1400 kg
height, h = 16 m
initial velocity, u = 21 m/s
final velocity, v = 13 m/s
Work done by engine, We = 80 kJ
Let the work done by the friction force is Wf.
Use the work energy theorem
net work done = change in kinetic energy
work done by engine + work done by friction force + work done by the gravitational force = Change in kinetic energy
80000 + Wf - m x g x h = 0.5 m ( v² - u²)
80000 + Wf - 1400 x 9.8 x 16 = 0.5 x 1400 x ( 169 - 441 )
- 139520 + Wf = - 190400
Wf = 50880 J
To solve this problem, we must imagine that Jim’s initial
position, the position of the rock, and Jim’s final position all connects to
form a triangle. Now we can imagine that the triangle is a right triangle with
the 90° angle on the initial position.
The angle of 30° is directly opposite to the length of his
total stride while the width of the river is the side adjacent to the angle.
Therefore can use the tan function to solve for the width of the river:
tan θ = opposite side / adjacent side
tan 30 = total stride distance / width of river
where total stride distance = 65 * 0.8 = 52 m
width of river = 52 m / tan 30
<span>width of river = 90.07 m</span>
Depending on the kind of electromagnetic field, nothing will happen.
