<em><u>The</u></em><em><u> </u></em><em><u>force</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>gravity</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>positive</u></em><em><u> </u></em><em><u>9</u></em><em><u>.</u></em><em><u>8m</u></em><em><u>/</u></em><em><u>s</u></em><em><u>^</u></em><em><u>2</u></em><em><u>.</u></em>
Answer:
(A) The maximum height of the ball is 40.57 m
(B) Time spent by the ball on air is 5.76 s
(C) at 33.23 m the speed will be 12 m/s
Explanation:
Given;
initial velocity of the ball, u = 28.2 m/s
(A) The maximum height
At maximum height, the final velocity, v = 0
v² = u² -2gh
u² = 2gh

(B) Time spent by the ball on air
Time of flight = Time to reach maximum height + time to hit ground.
Time to reach maximum height = time to hit ground.
Time to reach maximum height is given by;
v = u - gt
u = gt

Time of flight, T = 2t

(C) the position of the ball at 12 m/s
As the ball moves upwards, the speed drops, then the height of the ball when the speed drops to 12m/s will be calculated by applying the equation below.
v² = u² - 2gh
12² = 28.2² - 2(9.8)h
12² - 28.2² = - 2(9.8)h
-651.24 = -19.6h
h = 651.24 / 19.6
h = 33.23 m
Thus, at 33.23 m the speed will be 12 m/s
Answer:b
Explanation: i took the test and b was correct
Answer:
The amount of potential energy that was initially stored in the spring is 88.8 J.
Explanation:
Given that,
Mass of block = 1.60 kg
Angle = 30.0°
Distance = 6.55 m
Speed = 7.50 m/s
Coefficient of kinetic friction = 0.50
We need to calculate the amount of potential energy
Using formula of conservation of energy between point A and B



Put the value into the formula


Hence, The amount of potential energy that was initially stored in the spring is 88.8 J.
The steps are;
1- make an observation
2- ask questions
3- form a hypothesis
4- conduct an experiment
5- accept or reject your hypothesis