45. Review. Two constant forces act on an object of mass m = QC 5.00 kg moving in the xy plane as shown in Figure P7.45. Force F, is 25.0 N at 35.0°, and force F, is 42.0 N at 150°. At time t = 0, the object is at the origin and has velocity (4.00i2.50j m/s. (a) Express the two forces in unit-vector other answers notation. Use unit-vector notation for your (b) Find the total force exerted on the object. (c) Find the object's acceleration. Now, considering the instant t = 3.00 s find (d) velocity, (e) its position (f) its kinetic energy from m and (g) its the object's kinetic from 1500 energy m .T. (h) What conclusion can you 35.00 draw x m by comparing the answers to parts (f) and (g)? Figure P7.45

An electron is a subatomic particle (m= 9.11 x 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +7.31 x 105 m/s to a final velocity of 1.98 x 106 m/s while traveling a distance of 0.0545 m. The electron's acceleration is due to two electric forces parallel to the x axis: F₁ = 7.52 x 10-¹7 N, and F2, which points in the -x direction. Find the magnitudes of (a) the net force acting on the electron and (b) the electric force F2. F₁ F₁ F₂ F₁ (a) Number i (b) Number i VO X Units Units

Two constant forces act on an object of mass m = 4.30 kg object moving in the xy plane as shown in the figure below. Force F, is 26.5 N at 35.0°, and force F, is 48.0 N at 150°. At time t = 0, the object is at the origin and has velocity (3.50î + 2.15j) m/s. 150° 35.0° (a) Express the two forces in unit-vector notation. F, - 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. (f) Find its kinetic energy from V½mv2. kJ (g) Find its kinetic energy from 2mv,2 + EF · AF. kJ

9. a. An arrow is fired from a bow with a velocity of 69.2 m/s. The arrow has a mass of 0.082 kg. The arrow travels 0.855 m as it's being released/ while the force of the taunt string acts on it. What is the change in KE, AKE, of the arrow? 196.33 Previous submissions: b. What was the force of the bow string? 229.63 Previous submissions: J N V incorrect V incorrect