I need help! Thank you.

A 45kg skater and a 60kg skater are standing still, holding hands on frictionless ice. They push away from each other in opposit

frutty [35]

Answer:

The 60 kg skater is traveling at 2.63 m/s in the opposite direction from the 45 kg skater.

Explanation:

The velocity of the 60 kg skater can be found by conservation of linear momentum:

$P_{i} = P_{f}$

$m_{a}v_{i_{a}} + m_{b}v_{i_{b}} = m_{a}v_{f_{a}} + m_{b}v_{f_{b}}$ (1)

Where:

$m_{a}$ : is the mass of the first skater = 45 kg

$m_{b}$ : is the mass of the second skater = 60 kg

$v_{i_{a}}$ : is the initial speed of the first skater = 0 (he is standing still)

$v_{i_{b}}$ : is the initial speed of the second skater = 0 (he is standing still)

$v_{f_{a}}$ : is the final speed of the first skater = 3.5 m/s

$v_{f_{b}}$ : is the final speed of the second skater =?

By replacing the above values into equation (1) and solving for $v_{f_{b}}$ we have:

$0 = m_{a}v_{f_{a}} + m_{b}v_{f_{b}}$

$v_{f_{b}} = \frac{-m_{a}v_{f_{a}}}{m_{b}} = \frac{-45 kg*3.5 m/s}{60 kg} = -2.63 m/s$

The minus sign is because the 60 kg skater is moving in the opposite direction from the other skater.

Therefore, the 60 kg skater is traveling at 2.63 m/s in the opposite direction from the 45 kg skater.

I hope it helps you!

4 0

3 years ago

A baseball is hit from a height of 4 feet above the ground with an initial velocity of 110 feet per second and at an angle of 35

mrs_skeptik [129]

Answer:

Part a)

$h = 62.2 ft$

Part b)

It will not able to cross the pole

Explanation:

As we know that ball is hit with speed of 110 ft/s at an angle of 35 degree

so here we will say

$v_y = 110 sin35$

$v_x = 110 cos35$

now at the maximum height the vertical velocity will become zero

so here we can use kinematics

$v_f^2 - v_y^2 = 2 a h$

here we have

$a = -32 ft/s^2$

$v_f = 0$

$v_y = 63.1 ft/s$

now we have

$0 - 63.1^2 = 2(-32)h$

$h = 62.2 ft$

Part b)

now the height of ball is related to the distance from point of projection is given as

$y = xtan\theta - \frac{gx^2}{2v^2cos^2\theta}$

now we know that

$x = 375 ft$

$y = 375(tan35) - \frac{(32)(375^2)}{2(110^2)(cos35)^2}$

$y = 262.6 - 277.12 = -14.5 ft$

since its coming negative so it will not able to cross the pole

3 0

3 years ago

Elect the correct equations that show that when a 3.0-kg book is lifted 2.6 m its increase in gravitational potential energy is

grigory [225]

The increase in gravitational potential energy for an object of mass m is given by
$\Delta U = mg \Delta h$
where $\Delta h$ is the increase in altitude of the object.

In our problem, m=3.0 kg, $\Delta h= 2.6 m$ and $g=10 m/s^2$ (approximated value), so we have
$\Delta U = mg\Delta h=(3.0 kg)(10 m/s^2)(2.6 m)=78 J$

5 0

3 years ago

Fill in the blank. When the northern hemisphere experiences autumn, the southern hemisphere experiences __________.

Helga [31]

Answer:

When the northern hemisphere experiences autumn, the southern hemisphere experiences spring

Explanation:

When the northern hemisphere experiences autumn, the southern hemisphere experiences spring

This is due to the equinoxes. An equinox is an event that occurs twice a year. During these seasons all areas of the Earth's surface experience an equal amount of daylight and darkness. The sun is on the equator line, so the day and night in both hemispheres have the same duration. At that time the part of the Earth closest to the Sun is the equator.

The shape of the Earth means that while the spring equinox is experienced in the northern hemisphere, the autumn equinox is entered in the southern hemisphere.

8 0

4 years ago

Read 2 more answers

A student allows the evaporating dish and the anhydrous salt for a long time on the lab bench. What will happen to the mass of t

Olenka [21]

Anhydrous salts absorb moisture from their surroundings when it gets cooled, hence the mass of the content would increase. It can be prevented if we allow the evaporating dish to cool in a dessicator. A dessicator is a glass or plastic container in which chemicals can be stored and allowed to cool. This container can be sealed. Dessicator would provide an environment free of moisture instead of keeping in atmospheric air having moisture content.

4 0

3 years ago