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3 years ago

A ball is thrown straight up with a velocity of 50 m/s.(use g = -10 m/s^2) a) What is the velocity in m/s after 2 seconds?

Physics

1 answer:

Andrei [34K]3 years ago

3 0

Answer:

(a) 30 m/sec

(b) -50 m/sec

Explanation:

We have given initial velocity of ball u = 50 m/sec

Acceleration due to gravity $g=-10m/sec^2$

(a) Time t = 2 sec

Now according to first equation of v = u-gt

So v=50-10×2=30 m/sec

(b) Time t = 10 sec

Now according to first equation of motion

So final velocity v = u-gt = 50-10×10 =-50 m/sec

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Electric fish generate current with biological cells called electroplaques, which are physiological emf devices. The electroplaq

Harlamova29_29 [7]

Answer:

current in water = 0.924 A

Explanation:

Let the current in each row be i.

Thus, current in water is contributed by each row and total current in water becomes 140i.

We are given;

emf of each electroplaque = 0.15 V

Number of electroplaques = 5000

internal resistance = 0.25 Ω

resistance = 800Ω

Applying Kirchoff's Voltage Law to row and water, we have;

5000E − (5000r)i − 800(140i) = 0

Rearranging;

5000E = (5000r)i + 800(140i)

Plugging in the relevant values;

5000 x 0.15 = i((5000 x 0.25) + 112,000)

750 = 113,250i

i = 750/113,250

i = 0.0066 A

Recall earlier, the current in water is 140i.

Thus, current in water = 140 x 0.0066

= 0.924

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2 years ago

A uniform magnetic field is perpendicular to the plane of a circular loop of diameter 13 cm formed from wire of diameter 2.6 mm

I am Lyosha [343]

Answer:

Rate of change of magnetic field is $3.466\times 10^3T/sec$

Explanation:

We have given diameter of the circular loop is 13 cm = 0.13 m

So radius of the circular loop $r=\frac{0.13}{2}=0.065m$

Length of the circular loop $L=2\pi r=2\times 3.14\times 0.065=0.4082m$

Wire is made up of diameter of 2.6 mm

So radius $r=\frac{2.6}{2}=1.3mm=0.0013m$

Cross sectional area of wire $A=\pi r^2=3.14\times0.0013^2=5.30\times 10^{-6}m^2$

Resistivity of wire $\rho =2.18\times 10^{-8}m$

Resistance of wire $R=\frac{\rho L}{A}=\frac{2.18\times 10^{-8}\times 0.4082}{5.30\times 10^{-6}}=1.67\times 10^{-3}ohm$

Current is given i = 11 A

So emf $e=11\times 1.67\times 10^{-3}=0.0183volt$

Emf induced in the coil is $e=-\frac{d\Phi }{dt}=-A\frac{dB}{dt}$

$0.0183=5.30\times 10^{-6}\times \frac{dB}{dt}$

$\frac{dB}{dt}=3.466\times 10^3=T/sec$

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3 years ago

The figure shows a 1 cm cube that has a mass of 1 gram. Calculate the density of the cube in kg/m³.

dolphi86 [110]

Density = 1 g/cm^3 = 1000 Kg/m^3

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A car speed off around a bend at a constant 10m/s explain why it's velocity is not constant

VARVARA [1.3K]

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Hope this helps!

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