Two constant forces act on an object of mass m = 4.10 kg object moving in the xy plane as shown in the figure below. Force F with arrow1 is 24.5 N at 35.0°, and force F with arrow2 is 48.5 N at 150°. At time t = 0, the object is at the origin and has velocity (3.40î + 2.80ĵ) m/s. (a) Express the two forces in unit-vector notation.
F with arrow1 =
N
F with arrow2 =
N

(b) Find the total force exerted on the object.
N

(c) Find the object's acceleration.
m/s2

Now, consider the instant t = 3.00 s.
(d) Find the object's velocity.
m/s

(e) Find its position.
m

(f) Find its kinetic energy from ½mvf2.
kJ

(g) Find its kinetic energy from ½mvi2 + ΣF with arrow · Δvector r.
kJ

(h) What conclusion can you draw by comparing the answers to parts (f) and (g)?

a electromagnetic waves

wavelength divides in half and speed stays the same.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.