# phy

posted by
**patel**
.

Two constant forces act on an object of mass m = 4.50 kg object moving in the xy plane as shown in the figure below. Force 1 is 21.0 N at 35.0°, and force 2 is 47.0 N at 150°. At time t = 0, the object is at the origin and has velocity (3.70 + 2.25) m/s.

(a) Express the two forces in unit-vector notation.

1 = N

2 = 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 + Σ · Δ.

kJ

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