Ask question

Ask question

All categories

3 years ago

12

Ivan walks 10 meters west to the water fountain, then runs 2 meters east to his class to avoid a lockout. His displacement would

be;

2 answers:

otez555 [7]3 years ago

7 0

Answer:

<u>-8</u>

Explanation:

if he starts at ten and takes 10 steps left he'll be at -10... then if he takes 2 steps to the right , he's at -8 on the number-line

Komok [63]3 years ago

5 0

Answer:

The answer is 8 meters west

Explanation:

This answer is for quizizz website

You might be interested in

On my science test, there is a bonus question that I want to get right. Why would it be a bad idea to skydive on the moon? Hint:

eduard

Answer:

Because there is no air resistance

Explanation:

When an object falls on Earth, there are essentially two forces acting on it:

- The force of gravity, downward, equal to the weight of the object:

$W=mg$

where m is the mass and g the acceleration due to gravity

- The air resistance, F, which acts upward, and whose magnitude is generally proportional to v, the speed of the object

When the object starts its fall, its initial speed is zero: v = 0, so the air resistance is also zero: F=0, and the object accelerates downward due to gravity.

However, as it accelerates downward, its speed increases, and so does the air resistance F. However, F is upward, opposite to the direction of motion, therefore it reduces the net acceleration of the object; at a certain point, the magnitude of the air resistance will become equal to the weight, so that

mg = F

and at that point, the net acceleration of the object will become zero: this means that the object will continue its fall at a constant velocity, called terminal velocity.

On the Moon instead, there is no air resistance: this means that for an object falling down, the speed keeps increasing due to the effect of gravity, and it will never reach a terminal value: therefore, the final velocity at the impact will be much higher than on the Earth, if we assume the two objects have been dropped from a very high altitude from the surface.

7 0

3 years ago

A block (mass = 61.2 kg) is hanging from a massless cord that is wrapped around a pulley (moment of inertia = 1/2MR2 kg · m2, wh

kolezko [41]

Answer:

The angular velocity is $w = 53.35 \ rounds /minute$

Explanation:

From the question we are told that

The mass of the block is $m = 61.2kg$

The of the pulley is $M = 14.2 kg$

The radius of the pulley is $R = 1.5m$

The radius of the cord around the pulley is $r = 1.5 m$

The distance of the block to the floor is $d = 8.0 m$

From the question we are told that the moment of inertia of the pulley is

$I = \frac{1}{2} MR^2 kg \cdot m^2$

Substituting value

$I = \frac{1}{2} * 14.2 * (1.5)^2$

$I = 15.975 kg \cdot m^2$

Using the Newtons law we can express the force acting on the vertical axis as

$ma = mg -T$

=> $T = mg -ma$

Now when the pulley is rotated that torque generated on the massless cord as a r result of the tension T and the radius of the cord around the pulley is mathematically represented as

$\tau = I \alpha$

Here $\alpha$ is the angular acceleration

Here $\tau$ is the torque which can be equivalent to

$\tau = T r$

Substituting this above

$Tr = I \alpha$

Substituting for T

$(mg - ma ) r = I\ r \alpha$

Here $a$ is the linear acceleration which is mathematically represented as

$a = r\alpha$

$(mg - m(r\alpha ) ) r = I\ r \alpha$

$mgr = I\alpha + m(r\alpha ) r$

$mgr = \alpha [ I + mr^2]$

making $\alpha$ the subject

$\alpha = \frac{mgr}{I -mr ^2}$

Substituting values

$\alpha = \frac{61.2 * 1.5 * 9.8}{15.975 + (61.2 ) * (1.5)^2}$

$\alpha =5.854 rad /s^2$

Now substituting into the equation above to obtain the acceleration

$a = 5.854 * 1.5$

$a=8.78 m/s^2$

This acceleration is $a = \frac{v}{t}$

and v is the linear velocity with is mathematically represented as

$v = \frac{d}{t}$

Substituting this into the formula acceleration

$a = \frac{d}{t^2}$

making t the subject

$t = \sqrt{\frac{d}{a} }$

substituting value

$t = \sqrt{\frac{8}{8.78}}$

$t = 0.9545 \ s$

Now the linear velocity is

$v = \frac{8}{0.9545}$

$v = 8.38 m/s$

The angular velocity is

$w = \frac{v}{r}$

So

$w = \frac{8.38}{1.5}$

$w = 5.59 rad/s$

Generally 1 radian is equal to 0.159155 rounds or turns

So 5.59 radian is equal to x

Now x is mathematically obtained as

$x = \frac{5.59 * 0.159155}{1}$

$= 0.8892 \ rounds$

Also

60 second = 1 minute

So 1 second = z

Now z is mathematically obtained as

$z = \frac{ 1}{60}$

z $= 0.01667 \ minute$

Therefore

$w = \frac{0.8892}{0.01667}$

$w = 53.35 \ rounds /minute$

8 0

3 years ago

Please help with 9 & 10

Tanzania [10]

Add all the sec. and all the meter's and then add the meter's and sec. together

4 0

3 years ago

What is the efficiency (w/qh) of an ideal carnot heat engine operating between a hot region at t= 400 k and a cold one at t= 300

Vinvika [58]

The efficiency of an ideal Carnot heat engine can be written as:
$\eta = 1- \frac{T_{cold}}{T_{hot}}$
where
$T_{cold}$ is the temperature of the cold region
$T_{hot}$ is the temperature of the hot region

For the engine in our problem, we have $T_{cold}=300 K$ and $T_{hot}=400 K$ , so the efficiency is
$\eta= 1 - \frac{300 K}{400 K}=0.25$

4 0

2 years ago

Cloudy nights are usually warm because

almond37 [142]

Answer:

When you have a cloudy night, the clouds prevent heat from escaping through the atmosphere and into space.

The clouds act like a blanket and trap the heat it, and that is why every time you have a cloudy night, it is always warmer than a clear night.

5 0

2 years ago