All categories

3 years ago

Hicham El Guerrouj of Morocco holds the world record in the 1500 m running race. He ran the final 400 m in a time of 51.9 s.

Physics

1 answer:

konstantin123 [22]3 years ago

5 0

Answer: His average speed in mph over the last 400 m is 7.7 m/s.

Explanation:

Given: Hicham El Guerrouj of Morocco holds the world record in the 1500 m running race. He ran the final 400 m in a time of 51.9 s.

We know that , speed = $\dfrac{distance}{time}$

Here , distance = 400m and time = 51.9 s

Then, speed = $\dfrac{400}{51.9}\approx7.7\ m/s$

Hence, his average speed in mph over the last 400 m is 7.7 m/s.

You might be interested in

A 53 kg crate is at rest on a level floor, and the coefficient of kinetic friction is 0.36. The acceleration of gravity is 9.8 m

tino4ka555 [31]

Answer:

42.6 m

Explanation:

mass of crate m = 53 kg

coefficient of kinetic friction, μ = 0.36

acceleration due to gravity, g = 9.8 m/s^2

Force, F = 372.098 N

Net force, f = F - friction force

f = 372.098 - μ m x g = 372.098 - 0.36 x 53 x 9.8

f = 185.114 N

acceleration, a = f / m = 185.114 / 53 = 3.49 m/s^2

initial velocity, u = 0

time, t = 4.94 s

s = ut + 1/2 at^2

s = 0 + 1/2 x 3.49 x 4.94 x 4.94

s = 42.6 m

6 0

3 years ago

How the Law of Conservation of Matter is supported by the experimental demonstrations?

Delvig [45]

The law of conservation of matter states that matter cannot be created nor destroyed. It can only be transformed from one form to another. To state an example where this is shown, let's say a piece of paper is burning. Not having a scientific background, you would say that the matter is being destroyed. But in reality, the paper is simple being transformed to ash, carbon dioxide, and water vapor. Overall, the total mass would still remain the same.

6 0

3 years ago

A spherical balloon has a radius of 6.55 m and is filled with helium. The density of helium is 0.179 kg/m3, and the density of a

Ksju [112]

Answer:

$M_1 = 317.7 kg$

Explanation:

Mass of the helium gas filled inside the volume of balloon is given as

$m = \rho V$

$m = 0.179(\frac{4}{3}\pi R^3)$

$m = 0.179(\frac{4}{3}\pi 6.55^3)$

$m = 210.7 kg$

now total mass of balloon + helium inside balloon is given as

$M = 210.7 + 990$

$M = 1200.7 kg$

now we know that total weight of balloon + cargo = buoyancy force on the balloon

so we will have

$(M + M_1)g = \rho_{air} V g$

$(1200.7 + M_1) = (\frac{4}{3}\pi 6.55^3) (1.29)$

$1200.7 + M_1 = 1518.4$

$M_1 = 317.7 kg$

3 0

3 years ago

What is the value of R2 in this parallel circuit? (5 stars)

o-na [289]

Answer:

20 Ω

Explanation:

Voltage, current, and resistance are related by Ohm's law:

V = IR

40 V = (4 A) R

R = 10 Ω

The total resistance of the circuit is 10 Ω.

Resistors in parallel have a total resistance of:

1/R = 1/R₁ + 1/R₂

1 / (10 Ω) = 1 / (20 Ω) + 1/R₂

R₂ = 20 Ω

4 0

2 years ago

A light ray moving at a 54.3 deg

MrMuchimi

Answer:

$45.25^{\circ}$

Explanation:

Applying Snell's law

$n_1sin\theta_1 = n2*sin\theta_2\\1.33*sin(54.3) = 1.52*sin\theta_2\\sin\theta_2 = 1.33*0.81208353/1.52 = 0.71057\\\theta_2=sin^{-1} (0.71057)\\\theta_2 = 45.25^{\circ}$

3 0

3 years ago