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Natasha2012 [34]

4 years ago

14

The driver of a car moving with a constant speed applies the breaks, and the car comes to a stop after traveling 3.5 meters. Whi

ch force causes the deceleration of the car?

1 answer:

Ksivusya [100]4 years ago

8 0

Friction...............

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Suggest a reason for stirring energy powder in water

notsponge [240]

Answer:

The stirring allows fresh solvent molecules to continually be in contact with the solute. If it is not stirred, then the water right at the surface of the solute becomes saturated with dissolved sugar molecules, meaning that it is more difficult for the additional solute to dissolve.

Explanation: Help this helps :)))

6 0

3 years ago

If this decay has half-life of 2 years, how many years would it take for 10.8 g Protactinium-231 to remain given an initial mass

sergij07 [2.7K]

Answer:

Time = 6 years

Explanation:

First, we will calculate the no. of half life periods required to reduce the mass of Protactinium to the given value:

$m' = \frac{m}{2^{n} } \\\\2^n = \frac{m}{m'}$

where,

n = no. of half-life periods = ?

m = initial mass = 86.3 g

m' = remaining mass = 10.8 g

Therefore,

$2^n = \frac{86.3\ g}{10.8\ g}\\\\2^n = 8\\2^n = 2^3$

Since the bases are the same. Therefore equating powers:

n = 3

Now we calculate the time:

$Time = (n)(Half-Life)\\Time =(3)(2\ years)$

<u>Time = 6 years</u>

3 0

3 years ago

A ray diagram shows that an object is placed in front of a plane mirror. What are the characteristics of the image produced by t

romanna [79]

Same size as object should be the answer, it is a “plane” mirror

3 0

3 years ago

Read 2 more answers

Assume air resistance is negligible unless otherwise stated. Calculate the displacement in m and velocity in m/s at the followin

tankabanditka [31]

Answer: 1) t=0.5 s; S=6.225 m and v=14.9 m/s

2) t=1 s; S=14.9 m and v=19.8 m/s

3) t=1.5 s; S=26.05 m and v=24.7 m/s

Explanation:

The displacement $S$ is given by

$S=ut+\frac{1}{2} at^{2}$

and final velocity $v$ is given by

$v=u+at$

where $u$ is the initial velocity

$a$ is acceleration

$t$ is time taken

Case 1: when time is 0.5 s

The displacement is

$S=ut+\frac{1}{2} at^{2}\\S=10\times 0.5 +\frac{1}{2}\times 9.8\times 0.5^{2}\\\\S=6.225 m$

the velocity is

$v=u+at\\v=10+9.8\times 0.5\\v=14.9 m/s$

Case 2: when t=1 sec

The displacement is

$S=ut+\frac{1}{2} at^{2}\\S=10\times 1 +\frac{1}{2}\times 9.8\times 1^{2}\\\\S=14.9 m$

the velocity is

$v=u+at\\v=10+9.8\times 1\\v=19.8 m/s$

Case 3: t=1.5 s

The displacement is

$S=ut+\frac{1}{2} at^{2}\\S=10\times 1.5 +\frac{1}{2}\times 9.8\times 1.5^{2}\\\\S=26.05 m$

the velocity is

$v=u+at\\v=10+9.8\times 1.5\\v=24.7 m/s$

4 0

3 years ago

An object falls freely from rest near the surface of Earth. What is the speed of the object after having fallen a distance at 4.

bija089 [108]

V^2 = vi^2 + 2as

vi = 0 in this case
a = 9.8 m/s^2

So,

V^2 = 2 * 9.8 * 490
v = 98.05 m/s

hope this helps

3 0

3 years ago

Read 2 more answers