The equivalent resistance when two resistors are connected in series is
the sum of their individual resistances.
The marking on the resistor that says "1000 W" is the rating that tells
how much power the resistor can safely dissipate, without overheating
or exploding. (The 'W' stands for 'Watts'.) It doesn't tell us anything about
their individual resistances. So we don't have enough information to calculate
their series equivalent.
Light gates are more reliable. When using a manual stop watch, it is difficult to stop it at an exact time. A light gate is able to detect when an object passes through a 'gate' with the infrared transmitter and receiver.
a. We can calculate the amount of work by calculating the area under the graph.
first area (rectangular): 2.5 x 6 = 15
second area(trapezoid): 1/2 x (6+10) x 2.5 =20
total work done: 35 J
b. the force was first applied = 6 N
F = m.a
a = 6 : 3 = 2 m/s²
vf²=vi²+2as
vf²=6²+2.2.5
vf²=56
vf=7.5 m/s
