(adsbygoogle = window.adsbygoogle || []).push({}); 1. The rotating blade of a hovering helicopter sweeps out an area of radius 4m imparting a downward velocity of 12ms^-1 to the air displaced. Find the mass of the helicopter.

(g=10ms^-2, density of air= 1.3 kgm^-3)

3. The attempt at a solution

F=d/dt(mv)

F= (density of air*volume)*12

= 1.3*pie*16*12*12

=9409N

mass of helicopter= 940kg (the answers matched, but is it worked correct?)

2. The speed of rotation of the blades of the helicopter in question 1 is increased so that the air now hasa downward velocity of 13ms^-1. Find the upward acceleration of the helicopter.

attempt at the solution

F=mv

11043N=1.3(pie*16*13*13

F=ma

11043N=940*a

11043/940=a

Actual answer= 1.7ms^-2

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Is the first question worked right and any hints on the second please

**Physics Forums | Science Articles, Homework Help, Discussion**