What is a normal force?

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

3 years ago

Can you do it for me pls thank and if you do I mark you brainlies

Art [367]

Answer:

800pa

Explanation:

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6 0

2 years ago

Light of wavelength 436.1 nm falls on two slits spaced 0.31 mm apart. What is the required distance from the slits to the screen

kakasveta [241]

Answer:

The correct answer is "4.26 m".

Explanation:

Given:

Wavelength,

$\lambda = 436.1 \ nm$

or,

$=436.1\times 10^{-9} \ m$

Distance,

$d = 0.31 \ mm$

or,

$=0.31\times 10^{-3} \ m$

Distance between the 1st and 2nd dark fringes,

$(y_2-y_1) = 6\times 10^{-3} \ m$

As we know,

⇒ $\frac{d}{L} (y_2-y_1) = \lambda$

or,

⇒ $L=\frac{d(y_2-y_1)}{\lambda}$

By substituting the values, we get

$=\frac{0.31\times 6\times 10^{-6}}{436.1\times 10^{-9}}$

$=\frac{0.31\times 6\times 10^3}{436.1}$

$=\frac{1860}{436.1}$

$=4.26 \ m$

3 0

3 years ago

An apple hanging from a limb has potential energy because of its height . If it falls ,what becomes of this energy just before i

sineoko [7]

Answer: Just before its hits the ground it becomes kinetic energy and when it hits the ground it becomes in another form of energy (acoustic energy or thermal energy, for example)

Explanation:

Energy is the ability of matter to produce work in the form of movement, light, heat, among others.

In this sense, according to the Conservation of Energy principle: <em>"energy is not created or destroyed, it is transformed."</em>

So, in the case of the apple, its total energy is conserved.

When the apple is hanging from a limb, it has zero kinetic energy $K_{o}=0$ (because it is at rest) and has gravitational potential energy $U_{o}$ , which depends on the mass $m$ , the acceleration due gravity $g$ and the height $h$ :

$U_{o}=mgh$

When the apple falls, just before its hits the ground, this gravitational potential energy transforms in kinetic energy $K_{1}$ (since the apple is moving), which depends on the mass and velocity $V$ of the apple:

$K_{1}=\frac{1}{2}mV^{2}$

When the apple hits the ground, the gravitational potential energy is zero (h=0) and the kinetic energy transforms into some other form of energy (acoustic energy or thermal energy, for example).

3 0

3 years ago

If the object is placed 6 cm from a concave mirror the image distance 12 cm what is the image discige of the objects move from t

Alika [10]

Answer:

The image distance is -9.3cm.

6 0

2 years ago