Question

A bicycle travels $3.2km$ due east in $0.1h$, the $3.2km$ at $15.0$ degrees east of north in $0.21h$, and finally another $3.2km$ due east in $0.1h$ to reach its destination. The time lost in turning is negligible. What is the average velocity for the entire trip? (in km/h)

• A. $20$
  
• B. $21$
  
• C. $19$
  
• D. $30$
  

Answer 1

The correct option is C $19$

Total displacement in x-direction$=3.2+3.2\sin 15+3.2=7.23km$

Total displacement in y-directiin$=3.2\cos 15=3.1km$

Total displacement $=7.87$

Total time taken$=0.1+0.21+0.1=0.41h$

Avg. Velocity$=\frac{7.87}{0.41}=19kmph$

Hence correct answer is option $C$