Question

a model rocket is launched at an angle of 55 to the horizontal with a momentum of 20 kg-m/. If the vertical component of its velocity is 40 m/s what is the mass of the rocket?

Answer 1

`Given:\\ \alpha =55^\circ\\p=20kg\cdot (m)/(s) \\v_v=40 (m)/(s) \\\\Find:\\m=?\\\\Solution:\\\\p_v=mv_v\Rightarrow m= (p_v)/(v_v) \\\\ (p_v)/(p) =\cos \alpha \Rightarrow p_v=p\cos \alpha \\\\m= (p\cos \alpha )/(v_v) \\\\m= (20kg\cdot (m)/(s) \cdot \cos 55^\circ )/(40 (m)/(s) ) \approx 0.287kg=287g`