91.4k views
1 vote
Batman shoots a grappling hook

34.6 m/s at an 80.2° angle. What is the magnitude only (no direction) of the velocity of the hook 1.09 s later?

(Unit = m/s)

User Btimby
by
8.0k points

1 Answer

1 vote

Answer:

24.132 m/s

Step-by-step explanation:

Note


U = Initial Velocity


U_x = Initial Horizontal Velocity


U_y = Initial Vertical Velocity


V = Final Velocity


V_x = Final Horizontal Velocity


V_y = Final Vertical Velocity


B = launch angle


g = gravity


t = time


U_x=U*cos(B)


U_y=U*sin(B)

The horizontal component of the velocity is constant throughout the flight. So
U_x=V_x It can be defined as


V_x=U*cos(B)

We can use the kinematics equation


V=U+at

Gravity is acting downwards; gravity would be negative


V_y=U_y-gt

The magnitude of the velocity can be defined as


V=√(V_x^2+V_y^2)

Inserting some of the other equations gives us an equation at a given time (t).


V=√((U*cos(B))^2+(U*sin(B)-gt)^2)


V=\sqrt{(UcosB)^2+(UsinB)^2+(gt)^2-2gtU*sinB


V=√(U^2+g^2*t^2-2*t*g*U*sinB)


V(t)=√(U^2+g^2t^2-2tgUsinB)

We are given


U=34.6


B=80.2


t=1.09


g=9.81


V(1.09)=√(34.6^2+9.81^2*1.09^2-2*1.09*9.81*34.6*sin80.2)


V(1.09)=√(34.6^2+114.338-2*1.09*9.81*34.6*sin80.2)


V(1.09)=√(34.6^2+114.338-739.94868*sin80.2)


V(1.09)=√(34.6^2+114.338-729.151)


V(1.09)=√(1197.16+114.338-729.151)


V(1.09)=√(582.347)


V(1.09)=24.132

A rating/review would be much appreciated. Hope this helps!

Let me know if you have any questions about my work

User Remco Bakker
by
8.2k points