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solong [7]
3 years ago
12

what is required to cause a body of mass 500g to accelerate uniformly from rest across a smooth horizontal surface so that it wi

ll cover a distance of 20 tometre in 4 seconds .​
Physics
1 answer:
Y_Kistochka [10]3 years ago
8 0

A constant force of 1.25N

Explanation:

This is a kinematics problem.

First find acceleration,

then use F = ma to find force.

Given:

mass = .5kg

delta x = 20m

t = 4s

a = ?

Friction = 0

From the kinematics equations:

delta x = Vi + (1/2)at^2

Plug in terms that are given:

20m = 0 + (1/2)a(4^2)

(2*20m)/(16s^2) = a

40m/(16s^2)= 2.5m/s^2

Now use F = ma to find force exerted on object.

F = (0.5kg)*(2.5m/s^2)

F = 1.25N

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A proton moves perpendicularly to a uniform magnetic field b with a speed of 3.7 × 107 m/s and experiences an acceleration of 5
svlad2 [7]
The magnetic force experienced by the proton is given by
F=qvB \sin \theta
where q is the proton charge, v its velocity, B the magnitude of the magnetic field and \theta the angle between the direction of v and B. Since the proton moves perpendicularly to the magnetic field, this angle is 90 degrees, so \sin \theta=1 and we can ignore it in the formula.

For Netwon's second law, the force is also equal to the proton mass times its acceleration:
F=ma

So we have
ma=qvB
from which we can find the magnitude of the field:
B= \frac{ma}{qv}= \frac{(1.67 \cdot 10^{-27}kg)(5\cdot 10^{13}m/s^2)}{(1-6 \cdot 10^{-19}C)(3.7 \cdot 10^7 m/s)}=0.014 T
4 0
3 years ago
Why does an object in motion stay in motion unless acted on by an unbalanced force?
Svet_ta [14]

Answer: A) because forces are what stop and start motion

Explanation:

From Newton's first law, an object tends to stay in state of rest or motion unless acted upon by an unbalanced external force. This is also known law of inertia. This is because a force can stop or start a motion. A force cause body to accelerate to decelerate otherwise the body continues with constant speed.

7 0
3 years ago
Read 2 more answers
Possible reasons why seascorpions went extinct
BabaBlast [244]
Sea scorpions or Eurypterids lived about 251.9 million years ago. They were formidable predators and hunters, but they were wiped out in the Great Permian Mass Extinction, which is also known as the Great Dying (96% of all species on Earth went extinct).The largest species like Jaekelopterus was over 7 feet long! They were mainly thought to go extinct because of a slew of natural disasters that occurred when a comet hit the Earth, as well as increased volcanic activity polluting the seas that Sea scorpions lived in, as well as rising sea temperatures. The Silurian, when these Sea scorpions proliferated was when the water was cooler, holding in more nutrients, allowing both Sea Scorpions and other animals to spread all over the world. But as the oceans became polluted from the volcanoes (and the ash they produced) and the global ocean temperatures began to rise, many animals may not have been able to cope or adapt to the extreme change, becoming helpless in their nutrient deficient water (compared to what they were used to).

I hope this helps!
5 0
3 years ago
At what point in its motion is the KE of a pendulum bob a maximum? 1. The KE does not change. 2. at the lowest point 3. at the h
Andrew [12]

Answer:

2. at the lowest point

Explanation:

The motion of the pendulum is a continuous conversion between kinetic energy (KE) and gravitational potential energy (GPE). This is because the mechanical energy of the pendulum, which is sum of KE and GPE, is constant:

E = KE + GPE = const.

Therefore, when KE is maximum, GPE is minimum, and viceversa.

So, the point of the motion where the KE is maximum is where the GPE is minimum: and since the GPE is directly proportional to the heigth of the bob:

GPE=mgh

we see that GPE is minimum when the bob is at the lowest point,so the correct answer is

2. at the lowest point

3 0
3 years ago
A closely wound rectangular coil of 80 turns has dimensions 25.0 \rm cm by 40.0 \rm cm. The plane of the coil is rotated from a
Pepsi [2]

Answer:

88.3

Explanation:

Emf in a rotating coil is given by rate of change of flux:

E= dФ/dt=(NABcos∅)/ dt

N: number of turns in the coil= 80

A: area of the coil= 0.25×0.40= 0.1

B: magnetic field strength= 1.1

Ф: angle of rotation= 90- 37= 53

dt= 0.06s

E= (80 × 0.4× 0.25×1.10 × cos53)/0.06= 88.3V

4 0
3 years ago
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