Q. A 3.3 {rm kg} balloon is filled with helium (density = 0.179 {rm kg/m^ {3}}). If the balloon is the sphere with a radius of 5.1 {rm m}, what is maximum weight it can lift?

Q. A dog running in an open field has components of velocity v_x = 3.2 m/s and v_y = -2.1 m/s at time t_1 = 11.6 s. For a time interval from t_1 = 11.6 s to t_2 = 19.7 s, the average acceleration of the dog has magnitude 0.30 m/s^2 and direction 35.0^circ measured from the + x-{rm axis} toward the + y-{rm axis}.