Answer:
C.
Explanation:
A person pushing a couch will face resistive force of friction . When resistive force is greater then his force of effort , couch will not move. This force is static friction because the couch is stationary. When the force of effort is increased , magnitude of static friction also increases keeping the couch stationary. The ability of the static friction to increase its magnitude is limited by a maximum value beyond which the couch starts moving. The static friction is then converted into kinetic friction.
In rest of the three cases object is already moving so kinetic friction is in action.
I think it is (3) 690 N. You can use the theorem of Impulse and momentum where the impulse is equal to the change in momentum or:

(where f is for final and i for initial).
So you get:

83 km/h * 2.5 hours (3:30 - 1:00) = 207.5 km
207.5 km - 15 km = 192.5 km
You're thinking of Kepler's first law of planetary motion, but that's not
what it says.
First of all, Kepler didn't say anything about gravity. He only described
the orbits. And he said that the orbit of each planet is an <u>ellipse</u>, with the
sun at one focus.
If by some chance you're thinking of Newton ... he showed that <u>if</u> his formula for
gravity is correct, then the orbit of a planet <u>must</u> be an ellipse. But Newton's law
of gravity is not one of his so-called "three laws of motion".
Answer:
The magnitude of the magnetic field made by current in the wire is 3.064 x 10⁻⁶ T.
Explanation:
Given;
length of the straight wire, L = 0.56 m
conventional current, I = 0.4 A
distance of magnetic field from the wire, r = 2.6 cm = 0.026 m
To determine magnitude of magnetic field made by current in the wire, we will apply Bio-Savart Law;

Therefore, the magnitude of the magnetic field made by current in the wire is 3.064 x 10⁻⁶ T.