We can use the equation of motion:
s = ut + 1/2 x at²
Both the velocity and acceleration are downwards so we'll consider the downward direction positive
30 = 8t + 4.91t²
4.91t² + 8t - 30 = 0
Solving the quadratic:
t = 1.79 s; t = -3.42 s
Negative time is not possible so second value discarded. Time taken = 1.79 seconds
An example of an energy conversion that produces an unwanted form of energy is mixing acids with water.
Average speed = Distance ÷ Time
Distance = 38 m + 1/2 of 38 m = 38 + 19 = 57 m
Time = 9 + 1.8 = 10.8 s
Average speed = 57/10.8 = 5.277 m/s
Average Velocity = Displacement ÷ Time
Displacement = 19m
Time = 9 + 1.8 = 10.8 s
Average velocity = 1.759 m/s
Explanation:
work=force/distance
work=80
force=5
putting value of force and work we get
80=5/distance
5/80=distance
1/16=distance
or
0.0625m
6.25cm
Answer:
Work Done by the earth's gravitational force on the satellite as it travels from apogee to perigee is
W = F*D*Cos90° = 0
Explanation:
Although there is a change in the kinetic energy of the satellite at the apogee and perigee, the work done by the earth's gravitational force on the satellite is Zero.
W = F.D, F is the gravitational force, D is the displacement. Both F and D are vectors and perpendicular to each other. That is, the angle between F and D is 90°.