A steering wheel, a wrench, a screwdriver, and the back wheel of a bike are all examples of tools with a wheel and axle.
Answer:
When substances made of iron are exposed to oxygen and moisture (water), rusting takes place. Rusting removes a layer of material from the surface and makes the substance weak. Rusting is a chemical change.
Answer:
a) Yes
b) 7 rad/s
c) 0.01034 J
Explanation:
a)
Yes the angular momentum of the block is conserved since the net torque on the block is zero.
b)
m = mass of the block = 0.0250 kg
w₀ = initial angular speed before puling the cord = 1.75 rad/s
r₀ = initial radius before puling the cord = 0.3 m
w = final angular speed after puling the cord = ?
r = final radius after puling the cord = 0.15 m
Using conservation of angular momentum
m r₀² w₀ = m r² w
r₀² w₀ = r² w
(0.3)² (1.75) = (0.15)² w
w = 7 rad/s
c)
Change in kinetic energy is given as
ΔKE = (0.5) (m r² w² - m r₀² w₀²)
ΔKE = (0.5) ((0.025) (0.15)² (7)² - (0.025) (0.3)² (1.75)²)
ΔKE = 0.01034 J
Answer:
Frequency=10 Hz
Period=0.1 s
Explanation:
Frequency of a wave is the number of complete cycles per unit time. Usually, frequency is cycles per second, with unit as Heartz
Given cycles of the wave as 200 and time as 20 seconds
Frequency=200÷20=10 cycles per second
Therefore, frequency is 10 Hz
Period is usually the reviprocal of frequency hence reciprocal of 10 Hz will be 1/10=0.1 s
The answer is B. Weightlessness
