What keeps the Earth moving in its approximately circular path around the Sun? It's a combination of the 30 km/s speed of the Earth and the gravitational force exerted on the Earth by the Sun.

What would happen if the Earth was placed 150 million km from the Sun (its usual distance) and released from rest?

What would happen if the Earth's speed was 20% less than its current speed?

What would happen if the Earth's speed was 20% larger than its current speed?

What would happen if the Earth's speed was 50% larger than its current speed?