A good way for me to remember things is to study it, and to write it down! Say you want the formula for speed, I would write the formula multiple times on a piece of paper!
Here's a video that I haven't actually watched, I just looked it up! It might help you out though: <span>https://www.youtube.com/watch?v=-Wqrw4G79Kc</span>
Answer:
Echoes are the reflection of sound from relatively flat object that is far enough away that you can discern the time difference. Echoes are used to measure distance, velocity, and the shape of objects. Echoes off gratings result in an unusual pinging sound
I think its d, it is pointing to the whole circle which prob rlly makes it a proton
Answer:
(a)The work done by the man is -15.03J.
(b)The force exerted on the object is 127.4N.
Explanation:
Mass of the object pulled by the man is -13kg
Object is lifted 11.8 cm vertical with his teeth it means (displacement = +11.8cm = +0.118m)
Acceleration due to gravity is 
(a) <u>Calculating the work done</u>:
Work done = mgh
Where "m" is mass of an object, "g" is acceleration due to gravity and "h" is the displacement.
The work done by the man is -15.03J.
(b) <u>Calculating the force</u>:
Probably the man and the object are close to the exterior of the earth. If the rigidity required to maintained the object of consistent velocity interior the gravitational field of the earth is 
Thus the weight of the object is balanced by the force of the man's teeth on the object. That is
F = mg
F = 127.4N
The force exerted on the object is 127.4N.
Answer:
The force on the grass hopper is equal and opposite to the force on the wind shield.
Explanation:
It is a known fact every action has an equal and opposite reaction. Here the action force is the grasshopper hitting the windshield.
The reaction force is the force exerted by the windshield on the grasshopper.
If the force of windshield on the grasshopper is more, grasshopper would have been thrown away. If the grasshopper's force on the windshield is greater, the windshield would have broken.
But here these constitute equal and opposite action-reaction pair of forces and so the grasshopper is able to repeatedly strike the windshield.
