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Musya8 [376]
4 years ago
13

in a race, Usain Bolt accelerates at 1.99m/s^2 for the first 60.0m, then decelerates at -0.266m/s^2 for the final 40.0m. what wa

s his final velocity? (Unit = m/s)​
Physics
1 answer:
Paul [167]4 years ago
6 0

Answer:

14.7 m/s

Explanation:

During the first phase, given:

Δx = 60.0 m

v₀ = 0 m/s

a = 1.99 ms²

Find: v

v² = v₀² + 2aΔx

v² = (0 m/s)² + 2 (1.99 m/s²) (60.0 m)

v = 15.5 m/s

During the second phase, given:

Δx = 40.0 m

v₀ = 15.5 m/s

a = -0.266 ms²

Find: v

v² = v₀² + 2aΔx

v² = (15.5 m/s)² + 2 (-0.266 m/s²) (40.0 m)

v = 14.7 m/s

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Margaret is the new director of research at a well-known pharmaceutical company. She has been asked to design a set of research
Serjik [45]

Answer:

Double blind experiment

Explanation:

It is an experimental method , which helps to avoid any impartiality and any error due to biasing .

The experiment give rise to very accurate results , which is very important for any experiment .

Hence , the new director Margaret , need to design a set of double - blind experiments.

7 0
4 years ago
An ideal Diesel cycle has a compression ratio of 18 and a cutoff ratio of 1.5. Determine the (1) maximum air temperature and (2)
weqwewe [10]

Answer:

(1) The maximum air temperature is 1383.002 K

(2) The rate of heat addition is 215.5 kW

Explanation:

T₁ = 17 + 273.15 = 290.15

\frac{T_2}{T_1} =r_v^{k - 1} =18^{0.4} =3.17767

T₂ = 290.15 × 3.17767 = 922.00139

\frac{T_3}{T_2} =\frac{v_3}{v_2} = r_c = 1.5

Therefore,

T₃ = T₂×1.5 = 922.00139 × 1.5 = 1383.002 K

The maximum air temperature = T₃ = 1383.002 K

(2)

\frac{v_4}{v_3} =\frac{v_4}{v_2} \times \frac{v_2}{v_3}  = \frac{v_1}{v_2} \times \frac{v_2}{v_3} = 18 \times \frac{1}{1.5} = 12

\frac{T_3}{T_4} =(\frac{v_4}{v_3} )^{k-1} = 12^{0.4} = 2.702

Therefore;

T_4 = \frac{1383.002}{2.702} =511.859 \ k

Q_1 = c_p(T_3-T_2)

Q₁ = 1.005(1383.002 - 922.00139) = 463.306 kJ/jg

Heat rejected per kilogram is given by the following relation;

c_v(T_4-T_1)  = 0.718×(511.859 - 290.15) = 159.187 kJ/kg

The efficiency is given by the following relation;

\eta = 1-\frac{\beta ^{k}-1}{\left (\beta -1  \right )r_{v}^{k-1}}

Where:

β = Cut off ratio

Plugging in the values, we get;

\eta = 1-\frac{1.5 ^{1.4}-1}{\left (1.5 -1  \right )18^{1.4-1}}= 0.5191

Therefore;

\eta = \frac{\sum Q}{Q_1}

\therefore 0.5191 = \frac{150}{Q_1}

Heat supplied = \frac{150}{0.5191}  = 288.978 \ hp

Therefore, heat supplied = 215491.064 W

Heat supplied ≈ 215.5 kW

The rate of heat addition = 215.5 kW.

7 0
4 years ago
a graph is named mpg vs speed of a car traveling on a straight flat road. what does that name tell us about the graph
Fed [463]

It's a graph of a vehicle's fuel efficiency ... what operating speeds make it use more or less gas to go 1 mile.

7 0
4 years ago
Read 2 more answers
The elements carbon, nitrogen, and oxygen are'll part of the same _____ on the periodic table?
andreev551 [17]
C, N and O all belong to the same period, in which it's 2nd Period.
4 0
4 years ago
Read 2 more answers
A toaster uses 6700 joules of energy in 45 seconds to toast to a piece of bread what is power of the oven
just olya [345]
P= w/t and W= Work 
In this case, W= 6,700j, and T= 45 seconds
Power is the ratio of work  per unit time. When you perform a work in a given span of time, the ratio of work performed with respect to time is Called Power. 
si unit for Power is Watt (W) 
so, P= 6,700/45
P= 148 
Final answer is P=148
8 0
3 years ago
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