When practicing an oral presentation, you can prepare by writing a draft and practice reading aloud what you are going to say before your oral presentation.
Answer:
1) Time interval Blue Car Red Car
0 - 2 s Constant Velocity Increasing Velocity
2 - 3 s Constant Velocity Constant Velocity
3 - 5 s Constant Velocity Increasing Velocity
5 - 6 s Constant Velocity Decreasing Velocity
2) For Red and Blue car y₂ = 120 v = 
= 
= 20 m/s
We get the same velocity for two cars because it is the average velocity of the car at the given interval of time. It is measured for initial and final position.
3) At t = 2s, the cars are the same position, and are moving at the same rate
Position - same
Velocity - same
The position-time graph shares the same spot for two cars.
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:
840000 J/min
Explanation:
Area = A = 0.1 m²
Bottom of pot temperature = 200 °C
Thermal conductivity = k = 14 J/sm°C
Thickness = L = 1 cm = 0.01 m
Temperature of boiling water = 100 °C
From the law of heat conduction
Q = kAΔT/L
⇒ Q = 14×0.1×(200-100)/0.01
⇒ Q = 14000 J/s
Converting to J/minute
Q = 14000×60 = 840000 J/min
∴ Heat being conducted through the pot is 840000 J/min
