All categories

3 years ago

Shawn and his bike have a total mass of

Physics

1 answer:

Trava [24]3 years ago

3 0

Answer:

Shawn's kinetic energy is 61.45 J.

Explanation:

Given;

Mass of the system is, $m=52.3\ kg$

Displacement of the bike is, $d=1.6\ km=1.6\times 1000=1600\ m$

Time taken is, $t=17.4\ min=17.4\times 60=1044\ s$

Let the constant velocity be $v$ .

For constant velocity, magnitude of velocity is given as distance by time.

Therefore, $v=\frac{d}{t}=\frac{1600}{1044}=1.533\ m/s$

Now, kinetic energy of a body is given as:

$KE=\frac{1}{2}mv^2$

Here, $m=52.3\ kg,\ v=1.533\ m/s$

$\therefore KE=\frac{1}{2}\times 52.3\times (1.533)^2\\KE=0.5\times 52.3\times 2.35\\KE=61.45\ J$

Therefore, Shawn's kinetic energy is 61.45 J.

You might be interested in

Susan gently pushes the tip of her finger against the eraser on her pencil and the pencil does not move. Which of the

pochemuha

Answer: D. ➡️⬅️

Explanation: I just knew the answer ;)

6 0

3 years ago

find a magnitude of the force such that if the act at right angle there resultant is √10N but if the act of 50° the resultant is

Readme [11.4K]

Explanation:

Let magnitude of the two forces be x and y.

Resultant at right angle R1= √15N) and at

60 degrees be R2= √18N.

Now, R1 = √(x² + y²) = √15,

R2= √(x² + y² +2xycos50) = √18.

So x² + y² = 15,

and x² + y² + 1.29xy = 18,

therefore 1.29xy = 3,

y = 3/1.29x.

y = 2.33/x

Now, x2 + (2.33/x)2 = 15,

x² + 5.45/x² = 15

multiply through by x²

x⁴ + 5.45 = 15x²

x⁴ - 15x2 + 5.45 = 0

Now find the roots of the equation, and later y. The two values of x will correspond to the

magnitudes of the two vectors.

Good luck

7 0

3 years ago

Suppose you have two solid bars, both with square cross-sections of 1 cm2. They are both 24.6 cm long, but one is made of copper

vodka [1.7K]

Explanation:

Expression to calculate thermal resistance for iron ( $R_{I}$ ) is as follows.

$R_{I} = \frac{L_{I}}{k_{I} \times A_{I}}$

where, $L_{I}$ = length of the iron bar

$k_{I}$ = thermal conductivity of iron

$A_{I}$ = Area of cross-section for the iron bar

Thermal resistance for copper ( $R_{c}$ ) = \frac{L_{c}}{k_{c} \times A_{c}}[/tex]

where, $L_{c}$ = length of copper bar

$k_{c}$ = thermal conductivity of copper

$A_{c}$ = Area of cross-section for the copper bar

Now, expression for the transfer of heat per unit cell is as follows.

Q = $\frac{(100^{o} - 0^{o}}{\frac{L_{I}}{k_{I}.A_{I}} + \frac{L_{c}}{k_{c}.A_{c}}}$

Putting the given values into the above formula as follows.

Q = $\frac{(100^{o} - 0^{o})}{\frac{L_{I}}{k_{I}.A_{I}} + \frac{L_{c}}{k_{c}.A_{c}}}$

= $\frac{(100^{o} - 0^{o})}{21 \times 10^{-2} m[\frac{1}{73 \times 10^{-4}m^{2}} + \frac{1}{386 \times 10^{-4}m^{2}}}$

= 2.92 Joule

It is known that heat transfer per unit time is equal to the power conducted through the rod. Hence,

P = $\frac{Q}{T}$

Here, T is 1 second so, power conducted is equal to heat transferred.

So, P = 2.92 watt

Thus, we can conclude that 2.92 watt power will be conducted through the rod when it reaches steady state.

7 0

3 years ago

Wave crests in a pond are separated by 0.2m . The period of these waves is 0.2 s . What is the speed at which these waves travel

Ne4ueva [31]

1m per minute

or .5 m per 30 seconds

5 0

3 years ago

Provide descriptions and examples of the following forces: friction, gravity and elastic.

arsen [322]

Answer:

Friction:-

The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force - sliding and static friction. Though it is not always the case, the friction force often opposes the motion of an object. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing inter molecular attractive forces between molecules of different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together. The maximum amount of friction force that a surface can exert upon an

EG:-

A coaster sliding against a table.

Gravity:-

The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity that is directed "downward" towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found

EG:-

The force that causes a car to coast downhill even when you aren't stepping on the gas.

Elastic:-

Elasticity is the ability of a material to return to its original shape after being stretched or compressed. When an elastic material is stretched or compressed, it exerts elastic force. This force increases the more the material is stretched or compressed.

EG:-

An archer's stretched bow

5 0

3 years ago