You have to solve this by using the equations of motion:
u=3
v=0
s=2.5
a=?
v^2=u^2+2as
0=9+5s
Giving a=-1.8m/s^2
Then using the equation:
F=ma
F is the frictional force as there is no other force acting and its negative as its in the opposite direction to the direction of motion.
-F=25(-1.8)
F=45N
Then use the formula:
F=uR
Where u is the coefficient of friction, R is the normal force and F is the frictional force.
45=u(25g)
45=u(25*10)
Therefore, the coefficient of friction is 0.18
Hope that helps
The answer is C,<span> The sum of all forces acting on the object is zero. hope that helps!!</span>
Answer:
24cm/s
Explanation:
A=L*w
A'=L'*w'
L=13
w=5
L'=4
w'=6
A=?
A'=?
A=L*w
A=13*5
A=65
A'=L'*w'
A'=4*6
A'=24
*the given lengths are just to throw you off*
PART A)
Conductivity of insulator is very small as there is no free electrons to conduct the current trough that medium
So here number of conduction electrons are very less in insulators
PART B)
Resistance is the property of a conducting medium which will oppose the flow of current trough it
Resistance of wire directly depends on its length so resistance of long wire will be more than the resistance of short wire
Resistance inversely depends on the area so if a wire has more crossectional area then its resistance must be small
PART C)
power of light bulb is defined as rate of electrical energy
it is given by formula
P = i V
here we know that
i = 1.46 A
V = 120 volts
so power is given as


Here
- Acceleration and initial velocities are constant.
According to first equation of kinematics.




- Time was t at velocity v
- Time will be 4t at velocity 4v