Answer:
The work done required on the coin during the displacement is 21.75 w.
Explanation:
Given that,
A coin slides over a friction-less plane i.e friction force = 0.
The co-ordinate of the given point is (1.40 m, 7.20 m).
The position vector of the given point is represented by
.
The displacement of the coin is

The force has magnitude 4.50 N and its makes an angle 128° with positive x axis.
Then x component of the force = 4.50 cos128°
The y component of the force = 4.50 sin128°
Then the position vector of the force is


We know that,
work done is a scalar product of force and displacement.


=(-2.77×1.40+ 3.56×7.20) w
=21.75 w
The work done required on the coin during the displacement is 21.75 w.
Number of barrels are 3.0. Each barrel contains 42 gallons of oil. Thus, total volume of oil will be 42×3=126 gallons.
Converting gallons into m^{3}
1 gallon=0.00378 m^{3}
Thus, 126 gallons=0.4769 m^{3}
Thickness of oil film is 2.5\times 10^{2} nm, converting it into meters as follows:
1 nm=10^{-9} m
Thus,
2.5\times 10^{2} nm=1.5\times 10^{-7}m
Now, volume V of oil is related to area A and thickness T as follows:
V=A×T
rearranging,
A=\frac{V}{T}=\frac{0.4769 m^{3}}{2\times 10^{-7}m}=2.38\times 10^{6}m^{2}
Thus, square meters of oil will be 2.38\times 10^{6}m^{2}
Answer:
Velocity is the speed of something given in a direction. the SI unit of velocity is metre per second or m/s.
Explanation:
When a charged particle describes a circular path in a uniform magnetic field, the charged particle experiences a magnetic force towards the center of circular path, according to Fleming's left hand rule. Therefore the magnetic force and velocity (tangent to circular path) are perpendicular to each other during the circular motion. As the direction of displacement, is the direction of velocity, hence force and displacement are perpendicular to each other.
Therefore work done by magnetic force,
W=Fscos90=0