143°C = _____ 416 K -130 K 0 K 143 K

Atomic radius moving from left to right across a period,

Ilya [14]

Answer:

Atomic radius decreases moving from left to right across a period.

Explanation:

When we move left to right across a period, the size of atoms generally decreases. It is because within the period the outer electrons are in same valence shell and the number of electrons and proton increases moving from left to right across the the period. It increases the effective nuclear charge resulting in the increased attraction of electron to the nucleus that causes the decreased radius of the atoms.

6 0

3 years ago

An apple with mass 0.4 kg is hanging at rest from the lower end of a light vertical rope. A dart of mass 0.1 kg is shot vertical

Sholpan [36]

Answer:

The speed of the apple just after the collision is 1m/s

Explanation:

Since the two bodies collided, we will apply the law of conservation of momentum to find their common velocity which states that the sum of momentum of the bodies before collision is equal to the sum of momentum of the bodies after collision. After collision both bodies will move with a common velocity v.

Given momentum = mass × velocity

Initial momentum of the 0.4kg apple hanging at rest will be;

Momentum = 0.4kg×0m/s = 0kgm/s (the velocity of apple is 0m/s since it is hanging at rest)

Initial momentum of the 0.1kg dart moving with speed of 5m/s will be;

Momentum of dart = 0.1kg × 5m/s

Momentum of dart = 0.5kgm/s

Momentum of the bodies after collision will give;

Momentum after collision = (0.4kg+0.1kg) × v (v is their common velocity)

Momentum after collision = 0.5v

Using the law of conservation of momentum to calculate their common velocity, we will have;

0+0.5 = 0.5v

0.5 = 0.5v

v = 0.5/0.5

v = 1m/s

Therefore the speed of both bodies after collision is 1m/s which will also serve as the speed of the apple after collision.

5 0

3 years ago

Read 2 more answers

The froghopper Philaenus spumarius is supposedly the best jumper in the animal kingdom. To start a jump, this insect can acceler

Kay [80]

Answer:

Part a)

$v_f = 4 m/s$

Part b)

$t = 0.001 s$

Part c)

$d = 0.815 m$

Explanation:

Part a)

As we know that initially the grass hopper is at rest at the ground position

Now the acceleration is given as

$a = 4000 m/s^2$

distance of the legs that it stretched is given as

$s = 2.0 mm$

so we have

$v_f^2 - v_i^2 = 2 a d$

$v_f^2 - 0 = 2(4000)(0.002)$

$v_f = 4 m/s$

Part b)

time taken to reach this speed is given as

$v_f - v_i = at$

$4 - 0 = 4000 t$

$t = 0.001 s$

Part c)

as the grass hopper reach the maximum height its final speed would be zero

so we will have

$v_f^2 - v_i^2 = 2 a d$

$0 - 4^2 = 2(-9.81) d$

$d = 0.815 m$

5 0

3 years ago

The heat required to melt a piece of copper is (82 x 10 ^5 J). The heat of fusion of copper is (2.05×10 ^5 J/ kg). What is the m

Musya8 [376]

Answer:

Explanation:

Givens

Heat of Fusion = 2.05 * 10^5 J / kg watch the units.

Heat to actually melt the copper = 82 10^5 J

Formula

Mass of copper = Heat / Heat of Fusion

Solution

Mass of copper = 82*10^5 J / (2.05 * 10^5 J / kg)

Mass of copper = 40 kg

Notice that the kg is in the denominator of the second fraction. The rules of fractions would tell you the 1/1 / / 1 /kg . You take the right fraction and turn it upside down and multiply. 1 / 1 * kg/1 = 1* kg / 1*1 which is just kg.

Answer 40 kg of copper

4 0

2 years ago

A pendulum is swinging back and forth with a period of 2.0 seconds here on Earth. This pendulum is then brought to the Moon, whe

leonid [27]

Answer: The period of the pendulum will be bigger than in Earth.

Explanation:

The period of a pendulum is:

T = 2*pi*√(L/g)

where pi = 3.14

L is the length of the pendulum and g is the gravitational acceleration.

you can see that g is in the denominator, so if g is smaller, then the end number woll be bigger (because in the moon we are dividing by a smaller number)

This means that in the moon the period of the pendulum is bigger than in the Earth.

5 0

3 years ago