Answer:
A) x4
Explanation:
Magnification is equal to image size divided by the actual size, or M = I/A.
The image size is the student's drawing, which is 28.8 cm, and the actual size is 7.2 cm. Divide them, and cancel out the units, and you should get:
28.8 cm/7.2 cm = 4
We don't know, and we don't have enough information to calculate it.
The weight of the 60kg load is (m g) = 588 Newtons.
IF Hari wanted to<em> lift </em>the load 12m <em>straight up</em>, he would have to do
(Force x distance) = (588 N) x (12 m) = 7,056 Joules of work.
But to drag it, he has to provide enough force to balance out the force of friction, and we don't know how much that is. It depends on the weight of the load, the shape of the load, the smoothness of the part of the load that sits on the ground, and the smoothness of the ground. But the only thing we know is the weight of the load.
Answer; Ultrasonic waves (sounds having frequency greater than 20,000 Hz) are used in sonar because: ... Ultrasonic waves can penetrate water to long distances (because of their high frequency and very short wavelength), but ordinary sound waves or infrasonic waves cannot penetrate water to such long distances.