20- Two resistors R1 = 100 2 R2 = 220 22 are connected in series
across a voltage of 6.4 V.
a- Calculate the resistance of the resistor
equivalent to R1 and R2.
b- Calculate the current in the circuit.
C-
Calculate the voltages U1 and U2 across
R1 and R2 respectively.

Awheel rotates without friction about a stationary horizontal axis at the center of the wheel. a constant tangential force equal to 82.0 n is applied to the rim of the wheel. the wheel has radius 0.150 m . starting from rest, the wheel has an angular speed of 12.8 rev/s after 3.88 s. what is the moment of inertia of the wheel?

What do you think car designers do if the damage caused by a crash test is too severe?

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?