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3 years ago

On a velocity time graph, what happens when the line crosses the x axis?

Physics

1 answer:

Crank3 years ago

5 0

Answer:

the object is changing direction

Explanation:

During straight line motion, On a velocity vs. time graph, any time the line crosses the x axis, the object is changing direction

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If the scaled-up man now stands on one leg, what fraction of the tensile strength is the stress on the femur?.

Oksanka [162]

The fraction of the tensile strength which is the stress on the femur is 1.4%.

<h3>What is Tensile strength?</h3>

This is defined as the amount of load or stress that a material can handle before it stretches and breaks.

The femur which is located in the thigh is the largest bone in the body and it exerts a fraction of 1.4% tensile strength through the stress encountered on the femur when the man stands with one leg.

Read more about Tensile strength here brainly.com/question/25748369

5 0

2 years ago

A truck, initially at rest, rolls down a frictionless hill and attains a speed of 20 m/s at the bottom. To achieve a speed of 40

Crank

Answer:

To achieve the velocity of 40 m/sec height will become 4 times

Explanation:

We have given initially truck is at rest and attains a speed of 20 m/sec

Let the mass of the truck is m

At the top of the hill potential energy is mgh and kinetic energy is $\frac{1}{2}mv^2$

So total energy at the top of the hill $=mgh+0=mgh$

At the bottom of the hill kinetic energy is equal to $\frac{1}{2}mv^2$ and potential energy will be 0

So total energy at the bottom of the hill is equal to $0+\frac{1}{2}mv^2$

Form energy conservation $mgh=\frac{1}{2}mv^2$

$v=\sqrt{2gh}$ , for v = 20 m/sec

$20=\sqrt{2\times 9.8\times h}$

Squaring both side

$19.6h=400$

h = 20.408 m

Now if velocity is 0 m/sec

$40=\sqrt{2gh}$

$19.6h=1600$

h = 81.63 m

So we can see that to achieve the velocity of 40 m/sec height will become 4 times

5 0

3 years ago

In which of the following situations is consciousness NOT involved?

schepotkina [342]

Sleep walking definitely

6 0

4 years ago

Potassium is a crucial element for the healthy operation of the human body. Potassium occurs naturally in our environment and th

Mariulka [41]

Answer:

a) 0.0288 grams

b) $2.6*10^{-10} J/kg$

Explanation:

Given that:

A typical human body contains about 3.0 grams of Potassium per kilogram of body mass

The abundance for the three isotopes are:

Potassium-39, Potassium-40, and Potassium-41 with abundances are 93.26%, 0.012% and 6.728% respectively.

Thus; a person with a mass of 80 kg will posses = 80 × 3 = 240 grams of potassium.

However, the amount of potassium that is present in such person is :

0.012% × 240 grams

= 0.012/100 × 240 grams

= 0.0288 grams

the effective dose (in Sieverts) per year due to Potassium-40 in an 80- kg body is calculate as follows:

First the Dose in (Gy) = $\frac{energy \ absorbed }{mass \ of \ the \ body}$

= $\frac{1.10*10^6*1.6*10^{-14}}{80}$

= $2.2*10^{-10} \ J/kg$

Effective dose (Sv) = RBE × Dose in Gy

Effective dose (Sv) = $1.2 *2.2*10^{-10} \ J/kg$

Effective dose (Sv) = $2.6*10^{-10} J/kg$

5 0

4 years ago

Define torque qualitatively and quantitatively

andrezito [222]

The rotational effect of a force is called torque.it is the cause of rotation or angular deceleration

τ=rXF
where
τ = F r sin @
hope it helps

4 0

3 years ago