Question:
A 63.0 kg sprinter starts a race with an acceleration of 4.20m/s square. What is the net external force on him? If the sprinter from the previous problem accelerates at that rate for 20m, and then maintains that velocity for the remainder for the 100-m dash, what will be his time for the race?
Answer:
Time for the race will be t = 9.26 s
Explanation:
Given data:
As the sprinter starts the race so initial velocity = v₁ = 0
Distance = s₁ = 20 m
Acceleration = a = 4.20 ms⁻²
Distance = s₂ = 100 m
We first need to find the final velocity (v₂) of sprinter at the end of the first 20 meters.
Using 3rd equation of motion
(v₂)² - (v₁)² = 2as₁ = 2(4.2)(20)
v₂ = 12.96 ms⁻¹
Time for 20 m distance = t₁ = (v₂ - v ₁)/a
t₁ = 12.96/4.2 = 3.09 s
He ran the rest of the race at this velocity (12.96 m/s). Since has had already covered 20 meters, he has to cover 80 meters more to complete the 100 meter dash. So the time required to cover the 80 meters will be
Time for 100 m distance = t₂ = s₂/v₂
t₂ = 80/12.96 = 6.17 s
Total time = T = t₁ + t₂ = 3.09 + 6.17 = 9.26 s
T = 9.26 s
To solve this problem we will apply the concepts related to the calculation of power, from the two electrical forms:
Here,
V = Voltage
I = Current
R= Resistance
P = Power
PART A)
Replacing,
Resistance of bulb is 
PART B)
The bulb will draw 1.25A current
Explanation:
the answer is above with its si unit
Answer:
0 m/s²
Explanation:
Acceleration is the change in velocity over change in time. If the velocity is constant, then the acceleration is 0.
Answer:
30m/s
Explanation:
From law of motion equation
Vf= Vi + at
Where Vf= final velocity
Vi= initial velocity=0(the car started at rest)
a= acceleration= 3m/s2
t= time= 10s
Then substitute into the equation to get the final velocity.
Vf= 0+(10×3)
Vf= 30m/s
Hence, the car's final velocity is 30m/s
