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4 years ago

Consider the third period of the periodic table. Which element has the smallest atomic radius?

1 answer:

3 0

According to periodic trends in the periodic table, the atomic radius decreases from left to right.

In period three, the element with the smallest atomic radius would be the element in the rightmost area. Protons increase as it goes to the right, which would mean they pull in electrons closer which decreases the size.

So in period 3, the element with the smallest atomic radius is Argon (Ar).

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What force is necessary to accelerate a 50kg box at 30 m/s2?

sammy [17]

Answer:

F = m X a

Therefore ,

Force required = 50 X 30 = 1500 newton

6 0

3 years ago

1. If a car travels East 60 km for 4 hours. What was the velocity of the car?

True [87]

Answer:

15km/h East (15m/s East option)

Explanation:

Velocity = (change in) Distance/(change in) Time

The distance here is 60km, and the time is 4h, as given by the question. Therefore the velocity is 60km/4h = 15km/h.

To convert km/h to m/s, we just divide the value by 3.6, 15/3.6= 4.17m/s (2dp), which isn't actually an option here, so I'm assuming maybe a mistake in unit for the question?

'Velocity' is a vector quantity, meaning it has a size<em> </em>and a direction, as opposed to speed, a scalar quantity, which only has size. Therefore we need to add a direction for it to be velocity. The given direction here is east, so the velocity of the car is 15km/h East. (I would choose the 15m/s East as the question likely has a unit error and is closest.)

Hope this helped!

4 0

3 years ago

Car A starts out traveling at 35.0 km/h and accelerates at 25.0 km/h2 for 15.0 min. Car B starts out traveling at 45.0 km/h and

lawyer [7]

1 kilometre=1000 metre

1 hour = 3600 second

$1\ km/hr=\frac{1000}{3600} m/s$

$1\ km/hr=\frac{5}{18} m/s$

The initial velocity of car A is 35.0 km/hr i.e

$35.0\ km/hr=35*\frac{5}{18} m/s$

= 9.72 m/s

The initial velocity of car B is 45 km/hr =12.5 m/s

The initial velocity of car C is 32 km/hr = 8.89 m/s

The initial velocity of car D is 110 km/hr=30.56 m/s

The acceleration of car A is given as $25\ km/hr^2$

$=\ 25*\frac{1000}{3600*3600} m/s^2$

$=0.00192901234 m/s^2$

The time taken by car A = 15 min.

From equation of kinematics we know that-

v= u+at [Here v is the final velocity and a is the acceleration and t is the time]

Final velocity of A, v = 9.72 m/s +[0.00192901234×15×60]m/s

=11.456111106 m/s

The acceleration of B is given as $15\ km/hr^2$

$=0.00115740740740 m/s^2$

The time taken by car B =20 min

The final velocity of B is -

v= u+at

= u-at [Here a is negative due to deceleration]

=12.5 m/s +[0.0011574074074×20×60]

=13.8888888.....

=13.9

The acceleration of C is given as $40\ km/hr^2$

$=\ 0.003086419753 m/s^2$

The time taken by car C =30 min

The final velocity of C is-

v = u+at

=8.89 m/s+[0.003086419753×30×60] m/s

=14.4455555555..m/s

=14.45 m/s

The car C is decelerating.The deceleration is given as- $60\ km/hr^2$

$=0.0046296296296m/s^2$

The time taken by car D= 45 min.

The final velocity of the car D is-

v =u+at

=30.56 -[0.00462962962962×45×60]m/s

=18.06 m/s

Hence from above we see that the magnitude of final velocity car C and B is close to 15 m/s. The car C is very close as compared to car B.

3 0

3 years ago

What is the period of the kinetic or the potential energy change if the period of position change of an object attached to a spr

mylen [45]

Answer: 2.2 s

Explanation:

This is a simple harmonic motion problem. A simple Harmonic motion can be defined as special type of periodic oscillation where the restoring force is directly proportional to the displacement. The restoring force then acts in the direction opposite to the displacement.

All simple harmonic motion is sinusoidal.

PERIOD is the time required to complete a full cycle.

From the question, the period of position change of an object attached to a spring is 4.4 s. There are two potential energy and two kinetic energy maxima per period, therefore, we have 4.4/2 = 2.2 s.

3 0

3 years ago

3. How does the centripetal force change when

OLga [1]

Answer:

The centripetal force increases.

Explanation:

Centripetal force is given by $F_c=ma_c$ ; where $a_c=\frac{v^2}{r}$ .