Answer:
An <u>applied force</u> is a force that is applied to an object by a person or another object. If a person is pushing a desk across the room, then there is an applied force acting upon the object. The applied force is the force exerted on the desk by the person.
A <u>friction force</u> is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force - sliding and static friction. Though it is not always the case, the friction force often opposes the motion of an object. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing intermolecular attractive forces between molecules of different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together. The maximum amount of friction force that a surface can exert upon an object can be calculated using the formula below:
= µ •
No velocity will not be changed
Why?
According to Newtons 1st law the velocity of a moving object remains unchanged unless a external force affect that.
Answer:
a

b

Explanation:
From the question we are told that
The mass of the person is 
The speed of the person is 
The energy of the proton is 
Generally the de Broglie wavelength is mathematically represented as

Here h is the Planck constant with the value

So

=> 
Generally the energy of the proton is mathematically represented as

Here
is the mass of proton with value 
=> 
=> 
=> 
So

so 
=> 
The time the truck must apply the given force to increase its speed to given value is 5 s.
The given parameters;
- <em>applied force, F = 600 N</em>
- <em>mass of the truck, m = 1,500 kg</em>
- <em>speed of the truck, v = 2 m/s</em>
The force applied to the truck is determined by Newton's second law of motion; <em>which states that the force applied to an object is directly proportional to the product of mass and acceleration of the object.</em>
F = ma

Thus, the time the truck must apply the given force to increase its speed to given value is 5 s.
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Answer:
From smallest ratio to the largest ratio:
Coasting Universe - Critical Universe - Recollapsing Universe(From left to right)
Explanation:
The coasting universe is one that expands at a constant rate given by the Hubble constant throughout all of cosmic time. It has a ratio of actual density to critical density that is less than 1
The critical universe is one that is at balance with no expansion .I.e. the actual density and the critical density are equal, which makes the ratio of actual density to critical density to be equal to 1
Recollapsing Universe: The expansion of the universe reverses in the future and the universe eventually recollapses. The recollapsing universe has the ratio of the actual density to the critical density to be greater than 1