I don't like the wording of any of the choices on the list.
SONAR generates a short pulse of sound, like a 'peep' or a 'ping',
focused in one direction. If there's a solid object in that direction,
then some of the sound that hits it gets reflected back, toward the
source. The source listens to hear if any of the sound that it sent
out returns to it. If it hears its own 'ping' come back, it measures
the time it took for the sound to go out and come back. That tells
the SONAR equipment that there IS a solid object in that direction,
and also HOW FAR away it is.
RADAR works exactly the same way, except RADAR uses radio waves.
Answer: The correct answer is Image B.
Explanation: For an object to accelerate, there should be unbalanced forces present. An object will move in the direction of net force.
Balanced forces are defined as the forces acting on the same object which are equal in magnitude but act in opposite direction. The net forces are 0.
Unbalanced forces are defined as the forces acting on the same object which are unequal in magnitude. The net force is non-zero.
For the given images:
Image A: This box will accelerate easily because the net force is non-zero and is moving in right direction.
Image B: This box will not accelerate because the net force is zero as all the forces are balancing one another. Hence, the object will stay at rest.
Image C: This box will accelerate easily because the net force is non-zero and is acting in between the normal and applied force.
Image D: This box will accelerate easily because the net force is non-zero and is moving in right direction.
Hence, the correct option is Image B.
D. The liver's role is to remove harmful substances from the blood.
