it cant run fast if it is fat
Weight wouldn't effect speed but it would effect how quick it would get up to speed.
Weight
yes
The more weight the car has the slower it goes.
The weight, aerodynamics, horse power and gear ratios all affect the speed of an automobile.
It would affect its speed because the weight of the car is gonna slow it down
yes
Arrow dynamics
The speed of the bike has no effect on its weight. Weight = mass in kg x acceleration due to gravity, 9.8m/s2 on the earth.
As far as I know it shouldn't affect top speed (assuming that is the question). Weight will affect acceleration and therefore speed after a given amount of time or distance. An example would be 1/4 mile times at a race track. But top speed should be governed primarily by the wind resistance of the body, horsepower of the engine, and the overall gear ratio in top gear. Weight may affect rolling resistance slightly and therefore affect top speed but I suspect this affect would be negligible.
Yes. A heavier rocket will need more energy to achieve a certain speed.
Aerodynamics, weight of the car, horsepower of the engine, are all factors in the speed the car can travel.