When the rate of motion is the same direction the speed will decrease.<br><br> True<br> False

Nucleus A decays into the stable nucleus B with a half-life of 22.07 s. At t=0 s there are 1,293 A nuclei and no B nuclei. At wh

Alexeev081 [22]

Answer:

29.38 seconds

Explanation:

Half life, T = 22.07 s

No = 1293

Let N be the number of atoms left after time t

N = 1293 - 779 = 514

By the use of law of radioactivity

$N=N_{0}e^{-\lambda t}$

Where, λ is the decay constant

λ = 0.6931 / T = 0.6931 / 22.07 = 0.0314 decay per second

so,

$514=1293e^{-0.0314t}$

$2.5155=e^{0.0314t}$

take natural log on both the sides

0.9225 = 0.0314 t

t = 29.38 seconds

5 0

3 years ago

A girl on a bike is moving at a speed of 1.40 m/s at the start of a 2.45 m high and 12.4 m long incline. The total mass is 60.0

Scrat [10]

Answer:

Explanation:

Given that,

Initial speed of the girl is

u = 1.4m/s

Height she is going is

H = 2.45m

Incline plane she will pass to that height

L = 12.4m

Mass of girl and bicycle is

M=60kg

Frictional force that oppose motion is

Fr = 41N

Speed at lower end of inclined plane

V2 = 6.7m/s

Work done by the girl when the car travel downward

Using conservation of energy

K.E(top) + P.E(top) + work = K.E(bottom) + P.E(bottom) + Wfr

Where Wfr is work done by friction

Wfr = Fr × d

P.E(bottom) is zero, sicne the height is zero at the ground

K.E is given as ½mv²

Then,

½M•u² + MgH + W = ½M•V2² + 0 + Fr×d

½ × 60 × 1.4² + 60×9.8 × 2.45 + W = ½ × 60 × 6.7² + 41 × 12.4

58.8 + 1440.5 + W = 1855.1

W = 1885.1 —58.8 —1440.5

W = 355.8 J

8 0

3 years ago

The amplitude of a sound wave determines its

Savatey [412]

The Loudness i believe.

5 0

3 years ago

Read 2 more answers

If the magnitude of a charge is twice as much as another charge, but the force experienced is the same, then the electric field

Darina [25.2K]

Answer:

The new electric field strength of this charge is half of the strength of the other charge.

Explanation:

The electric force acting on the charge particle is given by :

F = q E

$E=\dfrac{F}{q}$

Where

q is the charged particle

E is the electric field

If the magnitude of a charge is twice as much as another charge, q' = 2q, but the force experienced is the same, then the new electric field is given by :

$E'=\dfrac{F}{q'}$

$E'=\dfrac{F}{(2q)}$

$E'=\dfrac{1}{2}\times \dfrac{F}{q}$

$E'=\dfrac{E}{2}$

So, the new electric field strength of this charge is half of the strength of the other charge. Hence, this is the required solution.

3 0

3 years ago

Which of the following physical properties makes copper and aluminum

GuDViN [60]

D. It is thermal conductivity because to work as a tool to heat things up it needs to conduct its temperature

4 0

2 years ago

When the rate of motion is the same direction the speed will decrease. True False