A car moving with a velocity of 20 meters/second has

1 answer:

5 0

Kinetic energy is the energy of an object in motion. It is expressed as the product of its mass and the square of its velocity. The opposite of this energy is called the potential energy, the energy of an object at rest. Calculations are as follows:

KE = mv^2
1.8x10^5 J = m(20 m/s)^2
m = 450 kg

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A negative charge is at rest at the origin of an axis system. Location x is at coordinate point (2m,3m) while location y is at (

Sergeu [11.5K]

The magnitude of the E-field decreases as the square of the distance from the charge, just like gravity.

Location ' x ' is √(2² + 3²) = √13 m from the charge.

Location ' y ' is √ [ (-3)² + (-2)² ] = √13 m from the charge.

The magnitude of the E-field is the same at both locations.

The direction is also the same at both locations ... it points toward the origin.

5 0

3 years ago

The half-life of Co-55 is 175 hours. How much of a 4000 g of Cobalt-55 sample would be left after 525 hours?

Harrizon [31]

We know that whatever amount we start with, half of it decays and forms atoms of other elements in 175 hours. So in order to figure out how much is left after 525 hours, we'll need to know how many half-lifes pass in that amount of time.

Well, (525 divided by 175) is exactly 3 half-lifes. So this will be easy.

-- After 1 half-life . . .

. . . . . 50% decays, 50% is still there.

-- After the 2nd half-life . . .

. . . . . (half of the leftover 50%) = another 25% decays, 25% is left.

-- After the 3rd half-life . . .

. . . . . (half of the leftover 25%) = another 12.5% decays, 12.5% is left.

12.5% of 4,000g = (0.125 x 4,000g) = 500 g .

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Another way:

After 1 half-life, 1/2 is left.

After 2 half-lifes, 1/4 is left.