Answer:
C - the runner starts slower and speeds up reaching ...
Answer:
a) 4.0 rad/s2
Explanation:
- For rigid bodies, Newton's 2nd law becomes :
τ = I * α (1)
where τ is the net external torque applied, I is the rotational inertia
of the body with respect to the axis of rotation, and α is the angular
acceleration caused by the torque.
- At the same time, we can apply the definition of torque to the left side of (1), as follows:
where τ = external net torque applied by Fnet, r is the distance
between the axis of rotation and the line of Fnet, and θ is the
angle between both vectors.
In this particular case, as Fnet is applied tangentially to the disk, Fnet
and r are perpendicular each other.
- Since left sides of (1) and (2) are equal each other, right sides are equal too, so we can solve for the angular acceleration as follows:
Wave speed (m/s) = frequency (Hz) x wave length (m)
=0.2 x 100= 20m/s
Answer:
Distance between them after 5 hours is 300 km.
Explanation:
From point A a vehicle leaves at 80 km / h at the same time a cyclist leaves at 20 km / h at what distance is they from each other after 5 hours.
Distance traveled by A in 5 hours = speed x time = 80 x 5 = 400 km
Distance traveled by B in 5 hours = speed x time = 20 x 5 = 100 km
The distance between them after 5 hours = 400 - 100 = 300 km