4. A lamp is connected to a 230 V mains supply. A current of 4 A flows through the lamp for 30 seconds.
4.1 Write down the equation that links charge flow, current, and time. (1 mark)

Explanation:Example

A 500 W television set is switched on for 4 hours. Calculate the energy transferred.

500 W = 500/1000 = 0.5 kW

energy transferred = power × time

= 0.5 × 4

= 2 kWh

I= Q ÷ T

Explanation:

I: Current measured in amperes

Q: Charge flow measured in coulombs

T: Time measured in seconds

I hope you find this helpful.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s