Answer: 
Explanation:
Given
Length of plank is 1.6 m
Force
is applied on the left side of plank
Force
is applied 43 cm from the left end O.
Mass of the plank is 
for equilibrium
Net torque must be zero. Taking torque about left side of the plank

Net vertical force must be zero on the plank

False the North Star never changes it position
Answer:
Current, I = 0.000109 Amps
Explanation:
Given the following data;
Voltage = 6V
Resistance = 55,000 Ohms
To find the current flowing through the circuit;
Ohm's law states that at constant temperature, the current flowing in an electrical circuit is directly proportional to the voltage applied across the two points and inversely proportional to the resistance in the electrical circuit.
Mathematically, Ohm's law is given by the formula;
Where;
V represents voltage measured in voltage.
I represents current measured in amperes.
R represents resistance measured in ohms.
Making current the subject of formula, we have;
Substituting into the formula, we have;
Current, I = 0.000109 Amps
Answer: 14. 49 m
Explanation:
We can solve this problem with the following equations:
(1)
(2)
Where:
is the horizontal distance between the cannon and the ball
is the cannonball initial velocity
since the cannonball was shoot horizontally
is the time
is the final height of the cannonball
is the initial height of the cannonball
is the acceleration due gravity
Isolating
from (2):
(3)
(4)
(5)
Substituting (5) in (1):
(6)
Finally: