An electron is moving at a speed of 4.8 × 10 6 m/s at an angle of 30.0° with respect to a uniform magnetic field of 9.2 × 10 –4 T. What is the radius of the resulting helical path? ( me = 9.11 × 10 –31 kg, qe = 1.60 × 10 –19 C)

r = 5.94 10⁻² m

Explanation:

The magnetic force is given by the ratio

        F =q v x B

The bold indicate vectors and the vector product determines that the force is perpendicular to the other two vectors, so the modulus of the velocity does not change, but its direction, therefore the acceleration in Newton's second law is centripetal

         F = m a

The magnitude of the force is

      F = q v B sin θ

The centripetal acceleration is

      a = v² / r

Let's replace

       q v B sin θ = m v² / r

       r = m v / (q B sin θ)

Let's calculate

      r = 9.11 10⁻³¹  4.8 10⁶ / (1.60 10⁻¹⁹  9.2 10⁻⁴ sin 30)

     r = 5.94 10⁻² m

the focus of lesson 1 is newton's first law of motion - sometimes referred to as the law of inertia. newton's first law of motion is often stated as. an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

explanation:

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask