Answer:
0.8 N
Explanation:
From coulomb's law,
Formula:
F = kqq'/r²........................ Equation 1
Where F = Force of repulsion, k = coulomb's constant, q = first positive charge, q' = second positive charge, r = distance between the charge.
Given: q = 20 μC = 20×10⁻⁶ C, q' = 100 μC = 100×10⁻⁶ C, r = 150 cm = 1.5 m.
Constant: k = 9×10⁹ Nm²/C²
Substitute these values into equation 1
F = (20×10⁻⁶ )( 100×10⁻⁶)(9×10⁹)/1.5²
F = 1800×10⁻³/2.25
F = 1.8/2.25
F = 0.8 N
Answer: 2000 watts
Explanation:
Given that,
power = ?
Weight of object = 200-N
height = 4 m
Time = 4 s
Power is the rate of work done per unit time i.e Power is simply obtained by dividing work by time. Its unit is watts.
i.e Power = work / time
(since work = force x distance, and weight is the force acting on the object due to gravity)
Then, Power = (weight x distance) / time
Power = (200N x 4m) / 4s
Power = 8000Nm / 4s
Power = 2000 watts
Thus, 2000 watts of power is needed to lift the object.
Answer:
a --> true, b --> false, c --> true, d -->false
Explanation:
a) since it stays floating the gravity force and the upqards push is the same
b) if it's balanced the rocket won't move from the ground, the force of the rocket, has to exceed the force of gravity
c) since it's going in a diretion the force of gravity is exceeding the force pushing it up
d) since that are speeding up at a rate, meaning growing, the force is unbalanced.
By law of refraction we know that image position and object positions are related to each other by following relation
here we know that
now by above formula
so apparent depth of the bottom is seen by the observer as h = 3.39 cm
The answer is C. Final position minus initial position.