Answer:
<u>40 m/s</u>
Explanation:
The final velocity of an object that experiences a period of acceleration is given by:
v - vi = A*t
Initial velocity, vi, is = 20m/s
Acceleration, A, is 4m/2^2
Time, t, is 5 seconds
v - vi = A*t
v - 20m/s = (4m/2^2)/(5 sec)
v = (20 m/s) + (20 m/s)
v = 40 m/s
No that is incorrect. If the results do not support the hypothesis than the hypothesis could have been incorrect. Or there is a possibility that the experiment was not done properly. A hypothesis is an educated guess for the results of the experiment.
If the sign of work is negative, that means the force and the motion are in opposite directions.
Let's say you see something roll off of the shelf. You catch it, and you let it down slowly and gently.
Gravity exerted down-force on it and it moved down. Gravity did positive work on it.
YOU exerted UP-force on it and it moved down. YOU did negative work on it.
(Also, the falling object exerted down-force on your hand, and your hand moved down. The falling object did positive work on your hand ! Where did THAT energy come from ? It came from the potential energy that the object had while it was on the shelf. Your hand absorbed that energy on the way down, doing negative work. So the object didn't have any kinetic energy when it reached the floor, and it did NOT splinter the floor or shatter in smithereens. It had barely enough energy left to make a sound when it hit the floor.)
<u>Answer:</u>
Mass of combined products = 20.4 grams
Mass of combined product and Erlenmeyer flask = 136 grams
<u>Explanation:</u>
By law of mass conservation, mass cannot be destroyed or created. So mass before reaction is mass after reaction.
Mass of lead(II) nitrate = 15.6 grams
Mass of potassium iodide = 4.8 grams
Mass of the Erlenmeyer flask = 115.6 grams
Mass of reactants = 15.6 + 4.8 = 20.4 grams
So mass of products = 20.4 grams
Mass of combined product and Erlenmeyer flask = 115.6 + 20.4 = 136 grams
