Answer:
a) The current is i = 1.2 A
b) The charge is Q = 17280 C
c) The energy is E = 43200 J
Explanation:
a) The current is given by the ohm's law wich is:
i = V/R = 3/2.5 = 1.2 A
b) Since the charge is steady we can use the following equation to find the charge amount in that time:
i = Q/t
Q = t*i
Where t is in seconds, so we have 4h * 3600 = 14400 s
Q = 1.2*14400 = 17280 C
c) The energy is the power delivered to the toy multiplied by the time:
P = 1.2*2.5 = 3 W
E = P*t = 3*14400 = 43200 J
Answer:
The instantaneous velocity of the rocket the moment before it hits the ground is 50 m/s.
Explanation:
Given;
initial velocity of the rocket, u = 50 m/s
Determine the maximum height reached by the rocket.
at maximum height reached by the rocket, the final velocity, v = 0
v² = u² -2gh
0 = 50² - 2(9.8)h
19.6h = 2500
h = 2500 / 19.6
h = 127.55 m
At maximum height, the time to reach ground is given by;
h = ¹/₂gt²

Before the rocket hits the ground the final velocity will be maximum;
v = u + gt
v = 0 + 9.8 x 5.1
v = 50 m/s
Therefore, the instantaneous velocity of the rocket the moment before it hits the ground is 50 m/s.
I say it is false that is the correct answer
Answer:
Area of the plates of a capacitor, A = 0.208 m²
Explanation:
It is given that,
Charge on the parallel plate capacitor, 
Electric field, E = 3.1 kV/mm = 3100000 V/m
The electric field of a parallel plates capacitor is given by :



A = 0.208 m²
So, the area of the plates of a capacitor is 0.208 m². Hence, this is the required solution.