Answer:
Resistance = 400000 Ohms
Explanation:
Given the following data;
Voltage = 1200 V
Current = 3 mA = 3/1000 = 0.003 A
To find the resistance;
Voltage = current * resistance
Resistance = 1200/0.003
Resistance = 400000 Ohms
Answer:
3.88m/s
Explanation:
Using the law of conservation of momentum
m1u1+m2u2 = (m1+m2)v
m1 and m2 are the masses
u1 and 2 are the initial velocities
v is the final velocity
Given
m1 = 64kg
u1 = 4.2m/s
m2 = 25kg
u2 = 3.2m/s
Required
Final velocity v
Substitute the given values into the formula
64(4.2)+25(3.2) = (65+25)v
268.8+80 = 90v
348.8 = 90v
v = 348.8/90
v = 3.88m/s
Hence the velocity of the kayak after the swimmer jumps off is 3.88m/s
Answer:
81 J.
Explanation:
From the question given above, the following data were obtained:
Specific heat capacity (C) = 0.45 J/gK.
Temperature change (ΔT) = 15 K
Mass = 12 g
Heat required (Q) =?
The heat required to raise the temperature of iron can be obtained as illustrated below:
Q = MCΔT
Q = 12 × 0.45 × 15
Q = 81 J
Therefore, the heat required to raise the temperature of the iron is 81 J.
<span>a = (v2 - v1)/t= acceleration formula
a = (70 - 0)/7
a = 10 km/hr/sec
-----
It's better to use as few units as possible.
10 km/hr = 10 km*1000 m/km/(1 hr*3600 sec/hr) = 25/9 m/sec
a= 25/9 m/sec/se</span>
Answer:
b) 900 W
Explanation:
The breaker trips when the current is equal to 20 A. The power (P) is the ddp (V) multiplied by the current. So, for the electric heater, the current is:
P = V*i
1500 = 120*i
i = 12.5 A
So, to become in 20 A, it's needed 7.5 A, which must come from the hairdryer. Its power must be:
P = 120*7.5
P = 900 W
