Find the radius of a cylindrical fire hose that is 200 ft long and has a volume of 39.25 ft*.

a train is moving with an initial velocity of 30 m/s, the brakes are applied so as to produce a uniform acceleration of -1.5 m/s

Pepsi [2]

Answer:

$\boxed{\sf Time \ in \ which \ train \ will \ come \ to \ rest = 20 \ sec}$

Given:

Initial velocity (u) = 30 m/s

Final speed (v) = 0 m/s

Acceleration (a) = - 1.5 m/,s²

To Find:

Time in which train will come to rest (t).

Explanation:

$\sf From \ equation \ of \ motion: \\ \sf \implies \bold{v = u + at} \\ \\ \sf Substituting \ value \ of \ v, \ u \ and \ a: \\ \sf \implies 0 = 30 + ( - 1.5)(t) \\ \sf \implies 0 = 30 - 1.5(t) \\ \sf \implies 30 - 1.5(t) = 0 \\ \\ \sf Subtract \: 30 \: from \: both \: sides: \\ \sf \implies (30 - \boxed{ \sf 30}) - 1.5(t) = \boxed{ \sf - 30} \\ \\ \sf 30 - 30 = 0 : \\ \sf \implies - 1.5(t) = - 30 \\ \\ \sf Divide \: both \: sides \: of \: - 1.5(t) = - 30 \: by \: - 1.5 : \\ \sf \implies \frac{ - 1.5(t)}{ \boxed{ \sf - 1.5}} = \frac{ - 30}{ \boxed{ \sf -1.5 }} \\ \\ \sf \frac{ \cancel{ \sf 1.5}}{\cancel{ \sf 1.5}} = 1 : \\ \sf \implies t = \frac{ - 30}{ - 1.5} \\ \\ \sf \frac{ - 30}{ - 1.5} = \frac{\cancel{ \sf 1.5} \times 20}{\cancel{ \sf 1.5}} = 20 : \\ \sf \implies t = 20 \: sec$

So,

Time in which train will come to rest = 20 seconds

4 0

2 years ago

Playing a certain musical note on a trumpet

Virty [35]

Answer:

(1) Resonance

Explanation:

Resonance is the process whereby a system is set into vibration due to the vibration of a nearby system with larger amplitude. The frequency at which this vibration takes place is called the resonant frequency.

It is a phenomenon of amplification that occurs when the frequency of a periodically applied force is in harmonic proportion to the natural frequency of the system on which it acts.

7 0

2 years ago

How is the Earth's magnetic field like a bar magnet's magnetic field?

valina [46]

In the outer layers of earths atmosphere gases are in ionized state primarily on account of cosmic rays . as earth rotates , strong electric current are set up due to movement of ions . these currents form earth magnetic field . and thus two equal and opposite poles of earth formed

8 0

2 years ago

A girl is floating in a freshwater lake with her head just above the water. If she weighs 610 N, what is the volume of the subme

Elden [556K]

Answer:

The volume of the submerged part of her body is $0.0622m^{3}$

Explanation:

Let's define the buoyant force acting on a submerged object.

In a submerged object acts a buoyant force which can be calculated as :

$B=$ ρ.V.g

Where ''B'' is the buoyant force

Where ''ρ'' is the density of the fluid

Where ''V'' is the submerged volume of the object

Where ''g'' is the acceleration due to gravity

Because the girl is floating we can state that the weight of the girl is equal to the buoyant force.

We can write :

$W_{girl}=B$ (I)

Where ''W'' is weight

⇒ If we consider ρ = $1000\frac{kg}{m^{3}}$ (water density) and $g=9.81\frac{m}{s^{2}}$ and replacing this values in the equation (I) ⇒

$B=W_{girl}$

$B=610N$

ρ.V.g = 610N

$1000\frac{kg}{m^{3}}.V.(9.81\frac{m}{s^{2}})=610N$ (II)

The force unit ''N'' (Newton) is defined as

$N=kg.\frac{m}{s^{2}}$

Using this in the equation (II) :

$(9810\frac{N}{m^{3}}).V =610N$

$V=\frac{610N}{9810\frac{N}{m^{3}}}$

$V=0.0622m^{3}$

We find that the volume of the submerged part of her body is $0.0622m^{3}$

8 0

2 years ago

A 6 kg bowling ball is accelerated at a rate of 2.3 m/s² down the lane. How much force was necessary to produce this acceleratio

ira [324]

According to Newton's 2nd law of motion:
F = m * a where F is the force applied in Newtons, m is the mass of the object in kg, and a is the acceleration of the object in m/ $s^{2}$ .
Therefore the force applied in this situation is simply:
F = 6 kg * 2.3 m/ $s^{2}$ = 13.8 N
Hope this helps!

6 0

2 years ago