- A fridge has a maximum static friction force
1 answer:
Answer:
They will move the fridge if they all push in the same direction, but it will not move with constant velocity
Explanation:
The maximum static friction force is
(negative sign since its direction is opposite to the push applied by the people)
Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:
This force is larger than the frictional force, so the fridge will start moving.
However, the net force on the fridge will be:
And according to Newton's second law,
where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant velocity.
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Answer:Zero
Explanation:
Given child moves the box with constant velocity over his head .
Force acting on box due to gravity is equal to his weight
Displacement of the box is Perpendicular to the direction of Applied force
Work done is given by
here is the angle between Force and displacement which is
so work done is zero
(a) See graph in attachment
The appropriate graph to draw in this part is a graph of velocity vs time.
In this problem, we have a horse that accelerates from 0 m/s to 15 m/s in 10 s.
Assuming the acceleration of the horse is uniform, it means that the velocity (y-coordinate of the graph) must increase linearly with the time: therefore, the velocity-time graph will appear as a straight line, having the final point at
t = 10 s
v = 15 m/s
(b)
The average acceleration of the horse can be calculated as:
where
v is the final velocity
u is the initial velocity
t is the time interval
In this problem,
u = 0
v = 15 m/s
t = 10 s
Substituting,
(c) 75 m
For a uniformly accelerated motion, the distance travelled can be calculated by using the suvat equation:
where
s is the distance travelled
u is the initial velocity
t is the time interval
a is the acceleration
In this problem,
u = 0
t = 10 s
Substituting,
(d) See attached graphs
In a uniformly accelerated motion:
- The distance travelled (x) follows the equation mentioned in part c,
So, we see that this has the form of a parabola: therefore, the graph x vs t will represents a parabola.
- The acceleration is constant during the motion, and its value is
(calculated in part b)
therefore, the graph acceleration vs time will show a flat line at a constant value of 1.5 m/s^2.
