How long will it take a horse to go from rest to 19 km/hr if it is accelerating at 5 km/hr 2 ?
1 answer:
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Answer:
2.7%
Explanation:
Given:
Uncertainty of the speedometer (u)= 2.5km/h
Speed measured at that uncertainty (v) = 92km/h
Percent uncertainty (p) is given as the ratio of the uncertainty to the speed measured then multiplied by 100%. i.e
p = %
p = %
p = 2.7%
Therefore, the percent uncertainty is 2.7%
Considering that the book is moving with constant speed, the force applied by Anna must be the same that the friction force:
If we clear the previous equation:
If we clear the previous equation:
Answer:
(a) 0.38 m
(b) 2.78 m/s
(c) 0.11 watt
Explanation:
mass, m = 0.3 kg
spring constant, K = 160 N/m
initial compression, d = 12 cm = 01.2 m
initial speed, u = 3 m/s
(a) Let the maximum stretch is y.
Use conservation of energy
Initial potential energy + initial kinetic energy = final potential energy
0.5 x K x d² + 0.5 x m x u² = 0.5 x K x y²
160 x 0.12 x 0.12 + 0.3 x 0.12 x 0.12 = 160 x y²
2.304 + 0.00432 = 160 y²
y = 0.38 m
y = 38 cm
(b) Let v is the maximum speed.
The speed is maximum when the stretch in the spring is zero, so by use of conservation of energy
Initial potential energy + initial kinetic energy = final kinetic energy
0.5 x K x d² + 0.5 x m x u² = 0.5 x m x v²
160 x 0.12 x 0.12 + 0.3 x 0.12 x 0.12 = 0.3 x v²
2.304 + 0.00432 = 0.3 v²
v = 2.78 m/s
(c) The time period of the spring mass system is given by
T = 0.272 second
Energy dissipated per cycle = 0.03 J
Power, P = 0.03 / 0.272 = 0.11 Watt