Answer:
Final velocity v = 8.944 m/sec
Explanation:
We have given distance S = 40 meters
Time t = 10 sec
As it starts from rest so initial velocity u = 0
From second equation of motion 


Now from first equation of motion
, here v is final velocity, u is initial velocity, a is acceleration and t is time
So 
Answer:
Approximately
, assuming that the volume of these two charged objects is negligible.
Explanation:
Assume that the dimensions of these two charged objects is much smaller than the distance between them. Hence, Coulomb's Law would give a good estimate of the electrostatic force between these two objects regardless of their exact shapes.
Let
and
denote the magnitude of two point charges (where the volume of both charged object is negligible.) In this question,
and
.
Let
denote the distance between these two point charges. In this question,
.
Let
denote the Coulomb constant. In standard units,
.
By Coulomb's Law, the magnitude of electrostatic force (electric force) between these two point charges would be:
.
Substitute in the values and evaluate:
.
Answer:
The time it will take for the car to reach a velocity of 28 m/s is 7 seconds
Explanation:
The parameters of the car are;
The acceleration of the car, a = 4 m/s²
The final velocity of the car, v = 28 m/s
The initial velocity of the car, u = 0 m/s (The car starts from rest)
The kinematic equation that can be used for finding (the time) how long it will take for the car to reach a velocity of 28 m/s is given as follows;
v = u + a·t
Where;
v = The final velocity of the car, v = 28 m/s
u = The initial velocity of the car = 0 m/s
a = The acceleration of the car = 4 m/s²
t = =The time it will take for the car to reach a velocity of 28 m/s
Therefore, we get;
t = (v - u)/a
t = (28 m/s - 0 m/s)/(4 m/s²) = 7 s
The time it will take for the car to reach a velocity of 28 m/s, t = 7 seconds.
Answer:
b. 3 times
Explanation:
Lets take
Coefficient for ordinary glass = α₁
Coefficient for pyrex glass = α₂
Given that α₁ = 3 α₂
Initial length of both glasses are equal = L
Change in the temperature is also same .= ΔT
We know that change in the length given as
ΔL = L α ΔT
Therefore


ΔL₁ = 3ΔL₂
Therefore change in the length of original glass is three time of pyrex glass.
b. 3 times