3 years ago

Suppose a runner completes one lap around a 400-m track in a time of 50 s. Calculate the average speed of the runner.

Physics

1 answer:

suter [353]3 years ago

6 0

Answer:

8m/s

Explanation:

Average Speed = distance / time = 400/50 = 8m/s

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The water flowing through a 2.0 cm (inside diameter) pipe flows out through three 1.3 cm pipes. (a) If the flow rates in the thr

Verdich [7]

Answer:

a)54L/min

b)0.845

Explanation:

a) A x V= $A_1V_1+ A_2V_2+A_3V_3$

where suffix 1,2,3 refers to the three pipes.

=27L/min+16L/min+11 L/min

=54L/min

b) A x V=54L/min => $\frac{\pi }{4} d^2$ x v

d= 2 cm

$\frac{\pi }{4} d^2$ x v = 54

v= $\frac{4}{\pi }$ x $\frac{54}{2^2}$

-> $A_1$ x $V_1$ =27L/min => $\frac{\pi }{4} d_1^2$ x $v_1$

$d_1$ = 1.3cm

$\frac{\pi }{4} d^2$ x $v_1$ = 27

$v_1$ = $\frac{4}{\pi }$ x $\frac{27}{1.3^2}$

Next is to find the ratio of speed i.e $\frac{v}{v_1}$

$\frac{4}{\pi }$ x $\frac{54}{2^2}$ / $\frac{4}{\pi }$ x $\frac{27}{1.3^2}$ => $\frac{54}{27}$ $\frac{1.3^2}{2^2}$

$\frac{v}{v_1}$ = 0.845

8 0

3 years ago

A skateboarder starting from rest accelerates down a ramp at 2 m/s for 2 s. What is the final speed of the skateboarder?

AlekseyPX

Answer: 4m/s

Explanation:

8 0

3 years ago

Attempt 3 of 2

Wewaii [24]

Answer:

mass.

Explanation:

other physical factors are changeable but the mass of a particular substance is always constant.

6 0

3 years ago

A dog jumps 0.80 m to catch a treat. The dog's displacement vector is shown below.

Brrunno [24]

Answer:D

Explanation:

It was right o khan academy

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3 years ago

A man, holding a weight in each hand, stands at the center of a horizontal frictionless rotating turntable. The effect of the we

Alex_Xolod [135]

Answer:

w = 2w₀ the angular velocity of man doubles

Explanation:

In this exercise, releasing the weights reduces the moment of inertia

I= I₀ / 2

Therefore, since the platform system plus man is isolated, the kinetic moment must be conserved

L₀ = L

I₀ w₀ = I w

I₀ w₀ = I₀ / 2 w

w = 2w₀

therefore the angular velocity of man doubles

7 0

3 years ago