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
Considering the total body, there are six elements of fitness: aerobic capacity, body structure, body composition, balance, muscular flexibility and strength
Answer:
48m
Explanation:
Given the following data;
Initial velocity = 0m/s
Final velocity = 6m/s
Time, t = 6 secs
Time, T2 = 5 secs
Mathematically, acceleration is given by the equation;
Substituting into the equation;
Acceleration, a = 1m/s²
<u>To find the distance covered in the first phase;</u>
<em>Solving for distance, we would use the second equation of motion;</em>
<em>Substituting the values into the equation;</em>
Distance, S1 = 18m
<u>For the second phase, time T2 = 5 secs;</u>
<em>Mathematically, speed is given by the equation;</em>
<em>Making distance the subject of formula, we have;</em>
<em>Substituting into the above equation;</em>
Distance, S2 = 30m
Total distance = S1 + S2 = 18m + 30m = 48m
Total distance = 48m
<em>Therefore, the total distance traveled by the biker is 48m.</em>
Answer:
B
Explanation:
F = ma , a = F/m
a1 = F/10 and a2 = F/4
Since Force is constant, a2 will we greater than a1
Derived quantities depend on.( fundamental)..........physical quantity
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