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3 years ago

An object of mass 2 kg starts from rest and is allowed to slide down a

Physics

1 answer:

WARRIOR [948]3 years ago

7 0

Answer: B

Explanation:

Given that an object of mass 2 kg starts from rest and is allowed to slide down a frictionless incline so that its height changes by 20 m.

The parameters given from the question are:

Mass M = 2kg

Height h = 20m

Let g = 9.8m/s^2

At the bottom of the incline plane, the object will experience maximum kinetic energy.

From conservative of energy, maximum K.K.E = maximum P.E

Maximum P.E = mgh

Maximum P.E = 2 × 9.8 × 20 = 392 J

But

K.E = 1/2mv^2

Substitute the values of energy and mass into the formula

392 = 1/2 × 2 × V^2

V^2 = 392

V = sqrt( 392 )

V = 19.8 m/s

V = 20 m/s approximately

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An electron moving in the direction of the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in

algol13

Answer:

- z axis

Explanation:

The magnetic force is perpendicular to its speed and the direction of the magnetic field, its equation being

F = q v x B

Where the bold indicates vectors, q is a positive charge,

The way to use this equation is with the rule of the right hand, the thumb points in the direction of the velocity, the other fingers extended in the direction of the magnetic field and the palm is the direction of the force for a positive charge.

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4 years ago

Larry , Moe, and Curly are pushing on a 25 kg crate. The crate is sitting on a horizontal floor, and the coefficient of kinetic

monitta

Answer:

2 m/s².

Explanation:

The forces acting on the crate have been shown in the figure below.

Net force acting on the crate in the horizontal direction = 400 - 250 = 150 N towards right.

For the forces of vertical direction we can write,

Normal force = 150 + Mg = 150 + 250 = 400 N (here g = 10 m/s² have been taken)

The magnitude of frictional force that will act on the crate = μ × Normal force

So, Frictional force = 0.25 × 400 = 100 N

Thus, the net force that will cause acceleration in the crate will be

Force in the right direction - frictional force

= 150 - 100 = 50 N

As we know,

Acceleration = $\frac{Force}{Mass}$ = $\frac{50}{25}$ = 2 m/s²

So, the net acceleration in the crate will be 2 m/s².

7 0

4 years ago

Find the noise level of a sound having an intensity of 1.5x10^-14W/m^2 given I0=10^12 W/m2

Llana [10]

Answer:

Noise level will be -18.2 watt

So option (b) will be correct answer

Explanation:

We have given sound intensity $I=1.5\times 10^{-14}w/m^2$

And threshold intensity $I_0=\times 10^{-12}w/m^2$ ( in question it is given as $10^{12}w/m^2$ but its standard value is $10^{-12}w/m^2$ )

Now noise level $=10log\frac{I}{I_0}=10log\frac{1.5\times 10^{-14}}{10^{-12}}=10log0.015-18.23$

So the noise level will be -18.2

So option (b) will be correct answer

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3 years ago

In an A.C circuit current leads voltage by phase π/2 then circuit is

aleksandrvk [35]

Answer:

capacitive

Explanation:

In a capacitive circuit, current is proportional to the derivative of the voltage. For a sinusoidal excitation, this means current is at the highest level when voltage is increasing through zero. That is, current leads the voltage.

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3 years ago

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I really don’t know this

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3 years ago