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miskamm [114]
3 years ago
9

Which sentence below describes a contact force? A) A baseball bat hits a ball B) A book falls to the floor C) A leaf floats in t

he air and falls to the ground D) A magnetic force pulls a paper clip toward a magnet Please help!!!
Physics
1 answer:
tester [92]3 years ago
6 0

A baseball bat hits a ball is an example of contact force.

Option A.

<h3><u>Explanation:</u></h3>

Contact force is defined as those forces which are acting between two bodies by actually touch between two bodies.

In case of the book falling to ground, the force acting is the gravitational force. Gravitational force acts even when two bodies aren't in contact. So its a non contact force.

Similar is the condition of the leaf and ground where the gravitational force acts.

The magnetic force between the paper clip and the magnet is also non contact force, which acts even when two bodies aren't in contact.

But the bat hitting the ball is having direct contact between the two bodies, and their contact is what makes the ball fly off. So its a contact force.

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If you walk 1.2 km north and then 1.6 km east, what are the magnitude and direction of your resultant displacement?
vodomira [7]

<u>Answer:</u>

 Option A is the correct answer.

<u>Explanation:</u>

  Let the east point towards positive X-axis and north point towards positive Y-axis.

 First walking 1.2 km north,  displacement = 1.2 j km

 Secondly 1.6 km east, displacement = 1.6 i km

 Total displacement = (1.6 i + 1.2 j) km

 Magnitude = \sqrt{1.2^2+1.6^2} = 2 km

 Angle of resultant with positive X - axis = tan^{-1}(1.2/1.6)=36.87^0 = 36.87⁰ east of north.

 

5 0
3 years ago
Scientific work is currently underway to determine whether weak oscillating magnetic fields can affect human health. For example
iragen [17]

Given Information:

Magnetic field = B = 1×10⁻³ T

Frequency = f = 72.5 Hz

Diameter of cell = d = 7.60 µm = 7.60×10⁻⁶ m

Required Information:

Maximum Emf = ?

Answer:

Maximum Emf = 20.66×10⁻¹² volts

Explanation:

The maximum emf generated around the perimeter of a cell in a field is given by

Emf = BAωcos(ωt)

Where A is the area, B is the magnetic field and ω is frequency in rad/sec

For maximum emf cos(ωt) = 1

Emf = BAω

Area is given by

A = πr²

A = π(d/2)²

A = π(7.60×10⁻⁶/2)²

A = 45.36×10⁻¹² m²

We know that,

ω = 2πf

ω = 2π(72.5)

ω = 455.53 rad/sec

Finally, the emf is,

Emf = BAω

Emf = 1×10⁻³*45.36×10⁻¹²*455.53

Emf = 20.66×10⁻¹² volts

Therefore, the maximum emf generated around the perimeter of the cell is 20.66×10⁻¹² volts

8 0
3 years ago
A boat travels north across a river at a velocity of 22 meters/second with respect to the water. The river's velocity is 2.2 met
MArishka [77]
The magnitude of the resultant is

         √ (22² + 2.2²)  =  √ (484 + 4.84)  =  √488.84  =  22.11 m/s .

The direction of the resultant is

         tan⁻¹(22N / 2.2E)  =  tan⁻¹(10)  =  5.71° east of north .
7 0
3 years ago
What is the speed of light? What is the speed of sound?
Rasek [7]

Answer:

speed of light simulating traveling at the speed of light. Speed of light, speed at which light waves propagate through different materials. In particular, the value for the speed of light in a vacuum is now defined as exactly 299,792,458 metres per second

The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium

8 0
3 years ago
A satellite is in a circular orbit about the earth (ME = 5.98 x 10^24 kg). The period of the satellite is 1.26 x 10^4 s. What is
Soloha48 [4]

Answer: V=5839.051m/s  

Explanation:

According to the <u>Third Kepler’s Law</u> of Planetary motion:

T^{2}=\frac{4\pi^{2}}{GM}a^{3}   (1)

Where;:

T=1.26(10)^{4}s is the period of the satellite

G is the Gravitational Constant and its value is 6.674(10)^{-11}\frac{m^{3}}{kgs^{2}}

M=5.98(10)^{24}kg is the mass of the Earth

a  is the semimajor axis of the orbit the satllite describes around the Earth (as we know it is a circular orbit, the semimajor axis is equal to the radius of the orbit).

On the other hand, the orbital velocity V is given by:

V=\sqrt{\frac{GM}{a}}   (2)

Now, from (1) we can find a, in order to substitute this value in (2):

a=\sqrt[3]{\frac{T^{2}GM}{4\pi}^{2}}   (3)

a=\sqrt[3]{\frac{(1.26(10)^{4}s)^{2}(6.674(10)^{-11}\frac{m^{3}}{kgs^{2}})(5.98(10)^{24}kg)}{4\pi}^{2}}   (4)

a=11705845.57m   (5)

Substituting (5) in (2):

V=\sqrt{\frac{(6.674(10)^{-11}\frac{m^{3}}{kgs^{2}})(5.98(10)^{24}kg)}{11705845.57m}}   (6)

V=5839.051m/s   (7)  This is the speed at which the satellite travels

6 0
3 years ago
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