Answer:
10 kg
Explanation:
Assuming a frictionless surface, then force F=ma where F is the applied force, m is the mass and a is acceleration. Making m the subject of the formula then 
Substituting 100 N for the applied force F and 10 m/s^2 for acceleration a then the value of m will be 
Therefore, in terms of kilograms, the bookshelf weighs 10 Kg
Answer:
W = 19.845 J
Explanation:
Work is defined as W = Fdcos
, where F is the force exerted and d is the distance. Because the direction the ball is falling is the same direction as the force itself,
= 0 deg, and since cos(0) = 1, this equation is equivalent to W = Fd. In this case, the force exerted is the weight force, which is equivalent to m * g. Substituting you get:
W = mgd = 0.810 kg * 9.8 m/s^2 * 2.5m
W = 19.845 J
The correct answer as the first one above !
Answer:
d = 19.796m
Explanation:
Since the ball is in the air for 4.02 seconds, the ball should reach the maximum point from the ground in half the total time, therefore, t=2.01s to reach maximum height. At the maximum height, the velocity in the y-direction is 0.
So we know t=2.01, vi=0, g=a=9.8m/s and we are solving for d.
Next, you look for a kinematic equation that has these parameters and the one you should choose is:

Now by substituting values in, we get
d = 19.796m
Answer:
776.6 w
1.04 hp
Explanation:
given:
Mass, m = 190kg
height change, h = 25m
time elapsed, t = 60 s
acceleration due to gravity, g = 9.81 m/s²
Potential energy required raising 190 kg of water to a height of 25m
= mgh
= 190 x 9.81 x 25
= 46,597.5 J
Power required in 60 s
= Energy required ÷ time elapsed
= 46,597.5 ÷ 60
= 776.6 Watts (Use conversion 1 W = 0.00134102 hp)
= 776.6 w x 0.00134102 hp/w
= 1.04 hp