Which of the following is most likely to be an observation made by a physiologist

In April 1974, Steve Prefontaine completed a 10 km race in a time of 27 min, 43.6 s. Suppose "Pre" was at the 8.13 km mark at a

SOVA2 [1]

Answer: $0.084 m/s^2$

Explanation:

Given

Total time=27 min 43.6 s=1663.6 s

total distance=10 km

Initial distance $d_1=8.13 km$

time taken=25 min =1500 s

initial speed $v_1=\frac{8.13\times 1000}{25\times 60}=5.6 m/s$

after 8.13 km mark steve started to accelerate

speed after 60 s

$v_2=v_1+at$

$v_2=5.6+a\times 60$

distance traveled in 60 sec

$d_2=v_1\times 60+\frac{a60^2}{2}$

$d_2=336+1800 a$

time taken in last part of journey

$t_3=1663.6-1560=103.6 s$

distance traveled in this time

$d_3=v_2\times t_3$

$d_3=\left ( 5.6+a\times 60\right )103.6$

and total distance $=d_1+d_2+d_3$

$10000=8.13\times 1000+336+1800 a+\left ( 5.6+a\times 60\right )103.6$

$1870=336+1800 a+\left ( 5.6+a\times 60\right )103.6$

$a=0.084 m/s^2$

5 0

3 years ago

A rocket blasts off vertically from rest on the launch pad with a constant upward acceleration of 2.30 m/s2. At 20.0 s after bla

lesya [120]

Answer:

Explanation:

v = u +at

u = 0

a = 2.3 m /s²

t = 20 s

v = 2.3 x 20

= 46 m /s

Distance covered under acceleration of 2.3 m/s²

s = ut + 1/2 at²

= 0 + .5 x 2.3 x 20²

= 460 m

After that it moves under free fall ie g acts on it downwards .

v² = u² - 2gh , h is height moved by it under free fall

0 = 46² - 2 x 9.8 h

h = 107.96 m

Total height attained

= 460 + 107.96

= 567.96 m

b ) At its highest point ,it stops so its velocity = 0

c ) rocket's acceleration at its highest point = g = 9.8 downwards .

At highest point , it is undergoing free fall so its acceleration = g

6 0

3 years ago

Describe a vector and how it is used

Ilia_Sergeevich [38]

Answer:

Vectors are used in science to describe anything that has both a direction and a magnitude. They are usually drawn as pointed arrows, the length of which represents the vector's magnitude.

Explanation:

They are usually drawn as pointed arrows, the length of which represents

8 0

3 years ago

Can someone explain how exactly to calculate the net force? Do you subtract the smaller number from the larger number? Any help

aleksley [76]

Explanation:

Let's say right is positive and left is negative.

F₁ = -150 N

F₂ = 220 N

Fnet = F₁ + F₂

Fnet = -150 N + 220 N

Fnet = 70 N

The magnitude of Fnet is 70 N, and since it's positive, the direction is to the right.

And since Fnet isn't 0, the force is unbalanced and the motion is changing.

3 0

3 years ago

Water is drawn from a well in a bucket tied to the end of a rope whose other end wraps around a solid cylinder of mass 50 kg and

sleet_krkn [62]

Answer:

$\alpha=78.4\ rad.s^{-2}$

Explanation:

Given:

mass of solid cylinder, $m=50\ kg$

diameter of cylinder, $d=0.25\ m$

mass of bucket of water, $m_w=20\ kg$

<em>When the bucket is released to fall in the well, it fall under the acceleration due to gravity.</em>

We have formula for angular acceleration as:

$\alpha=\frac{g}{r}$

where:

g = acceleration due to gravity

r = radius of the cylinder

$\aplha=\frac{9.8}{0.125}$

$\alpha=78.4\ rad.s^{-2}$

4 0

3 years ago