You swing a 2.2 kg stone in a circle with radius 75 cm. At what speed do you need to swing it so its centripetal acceleration will be 9.8 m/s^2?
27.1 m/s
2.7 m/s
7.35 m/s
8.6 m/s

3. a particle with initial velocity v⃗ 0=(5.85×103m/s)j^ enters a region of uniform electric and magnetic fields. the magnetic field in the region is b⃗ =−(1.35t)k^. you can ignore the weight of the particle. a. calculate the magnitude of the electric field in the region if the particle is to pass through undeflected, for a particle of charge +0.640 nc.