A car is pushed and travels 12 m. The same car is then pushed and it travels 15m. What could have happened? Select 2 answers.
The mass was decreased
The force was increased
The force was decreased
The mass was increased

Explanation:

If the force is kept the same, but the mass was decreased, then the car will travel further. The less mass an object has, the less inertia it has. Inertia is the tendency for the object to stay at rest if it's initially at rest (or the tendency for the object to stay in motion if already in motion).

If the mass is kept the same, but the force was increased, then the object will travel further than before. The same idea applies as discussed in the last paragraph.

If the force was decreased and mass kept the same, then there is less push, which results in the object traveling a shorter distance. If the mass is increased but the force kept the same, then the object moves a shorter distance because there's more inertia to overcome. There are more particles needed to be moved and they resist motion if at rest.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s