Correct Answers is A.
The machines gives us some mechanical advantage. This means the mechanical average makes the work output greater than the work input
Simple most example is a lever. The force applied is smaller and the output work is larger as compared to input.
Option B cannot be true, as there must be a force to get some work done.
Option C and D are inverse of what a machine is designed for. A small force can be exerted through a large distance to have a large force exerted through a small distance. Common Example of this principle is a screw opener.
Coals energy is affordable and it is easy to burn.
Answer:
770m/s
Explanation:
caculation using one of the newton law of motion
Answer:
The rate of the boat in still water is 44 mph and the rate of the current is 4 mph
Explanation:
x = the rate of the boat in still water
y = the rate of the current.
Distance travelled = 120 mi
Time taken upstream = 3 hr
Time taken downstream = 2.5 hr
Speed = Distance / Time
Speed upstream

Speed downstream

Adding both the equations


The rate of the boat in still water is <u>44 mph</u> and the rate of the current is <u>4 mph</u>
Presumably, the ball is kicked parallel to the ground below the cliff, so its altitude <em>y</em> at time <em>t</em> is

where <em>g</em> = 9.80 m/s^2 is the acceleration due to gravity.
The ball hits the ground when <em>y</em> = 0:


