Answer
given,
height of window = 4 m
time taken to travel = 1 s
acceleration due to gravity = 9.8 m/s²
u = -0.905 m/s
initial velocity of ledge v = 0
now,
v² = u² + 2 a s
(-0.905)² = 0 + 2 × 9.8 ×s
s = 0.042 m
Answer:
a) ω = 9.86 rad/s
b) ac = 194. 4 m/s²
c) minimum coefficient of static friction, µs = 19.8
Explanation:
a) angular speed, ω = 2πf, where f is frequency of revolution
1 rps = 6.283 rad/s, π = 3.142
ω = 2 * 3.14 * 0.25 * 6.28
ω = 9.86 rad/s
b) centripetal acceleration, a = rω²
where r is radius in meters; r = 200 cm or 2 m
a = 2 * 9.86²
a = 194. 4 m/s²
c) µs = frictional force/ normal force
frictional force = centripetal force = ma; where a is centripetal acceleration
normal force = mg; where g = 9.8 m/s²
µs = ma/mg = a/g
µs = 194.4 ms⁻²/9.8 ms⁻²
c) minimum coefficient of static friction, µs = 19.8
We are given an object that is speeding up on a level ground.
Let's remember that the gravitational energy depends on the change in height, therefore, if the object is not changing its height it means that the gravitational energy remains constant.
The kinetic energy depends on the velocity. If the velocity is increasing this means that the kinetic energy is also increasing.
Now, every change in velocity requires acceleration and acceleration requires a force. The force and the distance that the object moves are equivalent to the work that is transferred to the object and therefore, the change in kinetic energy. This means that the total energy of the system increases as work is transferred to the mass.
We have that the total energy of the system increases in the form of kinetic energy and that the gravitational potential energy remains constant. Therefore, the diagrams should look like pie charts that grow but the area of the segment of the potential energy stays the same. It should look similar to the following.
Average Velocity = Total Displacement / Total time
1st part of journey, 350 km at velocity 125 km/h
Time = 350 / 125 = 2.8 hours.
2nd part of journey, 220 km at velocity 115 km/h
Time = 220 / 115 = 1.9 hours
Average Velocity = Total Displacement / Total time
= (350 + 220) / (2.8 + 1.9)
= 570 / 4.7 ≈ 121.3 km/hr
Average Velocity ≈ 121 km/hr due south.
Option C.
Meters per second squared:
If you think about it, acceleration is about how fast speed changes. Speed is measured in meters per second:
So if you take that and just measure it over time, you get meters per second squared.
