Answer to Question #210503 in Mechanics | Relativity for buddy

Question

A 47.3 kg wheelchair rolls down a 17.4 m long ramp with an angle of inclination of 20.3° in 7.1 s. What is the power of gravity on the wheelchair?

Answer 1

Solution.

$m=47.3kg;$

$S=17.4m;$

$\alpha=20.3^o;$

$t=7.1s;$

$S=\dfrac{at^2}{2}\implies a=\dfrac{2S}{t^2};$

$a=\dfrac{2\sdot17.4}{7.1^2}=0.69m/s^2;$

$a_f=\sqrt{a^2+g^2+2gacos\alpha}=\sqrt{0.69^2+9.8^2+2\sdot0.69\sdot9.8\sdot0.9391}=10.45m/s^2;$

$F=ma_f;$

$F=47.3\sdot 10.45=494.3N;$

Answer: $F=494.3N.$