Answer:
120 rpm
Explanation:
I1 = 105 kgm^2, I2 = 70 kgm^2
f1 = 80 rpm, f2 = ?
Let the angular speed be f2 when his arms are tucked.
If no external torque is applied, then the angular momentum remains constant.
L1 = L2
I1 w1 = I2 w2
I1 x 2 x 3.14 x f1 = I2 x 2 x 3.14 x f2
105 x 80 = 70 x f2
f2 = 120 rpm
Answer: 0.78m/s^2
Explanation:
Force is the product of mass of an object and its acceleration.
i.e Force = Mass x Acceleration
In this case,
Force applied on cart = 35N
Mass of cart and contents = 45Kg
Acceleration = ?
Then, Force = Mass x Acceleration
35N = 45Kg x Acceleration
Acceleration = (35N/45kg)
Acceleration = 0.78 m/s^2 (The unit of acceleration is metre per second square)
Thus, the shopping cart moved with an accelerations of 0.78m/s^2
F=m∙a
m, mass = 8,000 kg
a, accelerating rate = 4 m/s2
F=8000*4
=32000 kg m/s2
=32000 N