A 65kg person has a weight of
2 answers:
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Answer:
where E = electric field intensity
Explanation:
As we know that plastic ball is suspended by a string which makes 30 degree angle with the vertical
So here force due to electrostatic force on the charged ball is in horizontal direction along the direction of electric field
while weight of the ball is vertically downwards
so here we have
since string makes 30 degree angle with the vertical so we will have
where E = electric field intensity
Answer:
Work done by external force is given as
Explanation:
As per work energy Theorem we can say that work done by all force on the car is equal to change in kinetic energy of the car
so we will have
now we have
so from above equation
so from above equation work done by external force is given as
Answer:
a) Gravitational potential energy = 399 J
b) Gravitational potential energy = 66.5 J
c) Gravitational potential energy = 0 J
Explanation:
Hi there!
Please, see the attached figure for a better understanding of the problem.
a) When the ropes are horizontal, the height of the child, relative to the child's lowest position, is 2.10 m (see figure).
The gravitational potential energy is calculated as follows:
PE = mgh
Where:
PE = potential energy.
mg = weight of the child
h = height.
Then when the ropes are horizontal, the potential energy will be:
PE = 190 N · 2.10 m = 399 J
b) When the ropes make a 34.0° with the vertical, the height of the child is 2.10 m minus x (see figure). To find x, we can use trigonometry of right triangles:
cos angle = adjacent side / hypotenuse
cos 34.0° = x / 2.10 m
x = 2.10 m · cos 34.0° = 1.75 m
Then, the height of the child relative to the lowest position is
(2.10 m - 1.75 m) = 0.35 m
Therefore, the gravitational potential energy will be:
PE = 190 N · 0.35 m
PE = 66.5 J
c) When the child is at the bottom of the circular arc the height is zero (the child is at the lowest position), then, the gravitational potential energy will be zero.
