The question is about unclear since no picture provided. But from the question, it could be guessed that the box is moving back and forth on the frictionless plane at the amplitude of A in simple harmonic motion.
Answer:
D. At x=0, it's acceleration is at a maximum
Explanation:
As the box move forward, it reaches point A and than move backward. Theoretically, the box will move backwards, through its origin, to point -A and then going forward.
Point A is the maximum displacement of the box in this case. At this point, the box instantaneously stop to go backward. Therefore the velocity at that moment is zero.
From point -A, the box travel forward and keep building up speed due to the release in potential energy of the spring. And at point x=0, the velocity become maximum. After point x=0, the velocity of the box slows down due to the conversion of kinetic energy to potential energy of the spring. And as it reaches point A, it reaches zero velocity.
The same can be said as the box travels backward from point A to -A
Answer:
Explanation:
Speed = distance / time
Velocity = displacement / time
So ,
Speed = 50 km / 0.5 hr = 100 km/h
Velocity = 40 km / 0.5hr = 80 km/h
Answer:
3 N to the right
Explanation:
There are two forces acting on the car:
- A force of 10 N towards the right
- A force of 7 N towards the left
Therefore, the net force is given by the difference between the two, since they are in opposite directions:

And the direction is to the right, since the force to the right has greater magnitude than the force to the left.
Answer:

Explanation:
the variations in riser height or tread depth should not be grater than
that is equal to 9.5 mm but the maximum riser height should be the
but variation in riser height should not exceed to
. The minimum riser height should be 7 inches which is equal to the 178 mm