Answer:
Calculating Coefficient of friction is 0.229.
Force is 4.5 N that keep the block moving at a constant speed.
Explanation:
We know that speed expression is as 
.
Where, 
is initial speed, V is final speed, ∆s displacement and a acceleration.
Given that,
=3 m/s, V = 0 m/s, and ∆s = 2 m
Substitute the values in the above formula,
0 = 9 - 4a
4a = 9
is the acceleration.
Calculating Coefficient of friction:
Compare the above equation
Cancel "m" common term in both L.H.S and R.H.S
Hence coefficient of friction is 0.229.
calculating force:
F = 4.5 N
Therefore, the force would be <u>4.5 N</u> to keep the block moving at a constant speed across the floor.
The frequency of a wave is the reciprocal of its period.
A period of 0.008 sec means a frequency of
1 / 0.008 sec = 125 per sec . (125 Hz)
the answer is d they are essential to all ecosystems
Answer:
Explanation:
For resistance of a wire , the formula is as follows
R = ρ L / S
where ρ is specific resistance , L is length and S is cross sectional area
Given L = 14 000 m ,
S = 4.8 x 10⁻⁴ m²
specific resistance of aluminum = 2.8 x 10⁻⁸ ohm-meter
Putting the values in the formula
R = 2.8 x 10⁻⁸ x 14 x 10³ / (4.8 x 10⁻⁴ )
R = 0.8167 ohm .
= .82 ohm .
Speed = (distance covered) / (time to cover the distance).
= (1.92 meters) / (4.47 x 10⁻⁸ second)
= 42,950,000 meters/second (rounded to the nearest 10,000 m/s)
That's about 96.1 million miles per hour, or about 14% of the speed of light.
