Answer:
the wagon should be used as frame of reference if an observer said the child was not moving.
Explanation:
The state of motion of a body depends upon the frame of reference. It is the set of co-ordinates according to which the motion is analyzed. If a child is riding in a wagon, then he will be considered in motion to a person standing outside the wagon. Hence, if we take a frame of reference outside the wagon then the child must be in motion with respect to the observer. On the other hand if the observer is inside the wagon, then the child must be in rest with respect to the observer. Hence, if we take the wagon to be the frame of reference, then the child will be at rest with respect to the observer.
<u>Therefore, the wagon should be used as frame of reference if an observer said the child was not moving.</u>
Since static friction is the minimum force required to just start the motion of a stationary object.
Here if we need to start an object from rest then we required F = 700 N
So for the first part of the above problem Force will be F = 700 N
Now if the box is already moving then we will have to use kinetic friction force between box and floor
now we can write the equation of net force as
here
now we will have
Answer:
=0.855V
Explanation:
The induced voltage can be calculated using below expression
E =B x dA/dt
Where dA/dt = area
B= magnetic field = 6.90×10-5 T.
We were given speed of 885 km/h but we will need to convert to m/s for consistency of unit
speed = 885 km/h
speed = 885 x 10^3 m/hr
speed = 885 x 10^3/60 x60 m/s
speed = 245.8 m/s
If The aircraft wing sweep out" an area
at t= 50.4seconds then we have;
dA/dt = 50.4 x 245.8
= 123388.32m^2/s
Then from the expression above
E =B x dA/dt substitute the values of each parameters, we have
E = 6.90 x 10^-5 x 12388.32 V
E =0.855V
Hence, the average induced voltage between the tips of the wings is =0.855V
