Acar speeds up from 15 m/s to 30 m/s in 12 seconds. what is the acceleration of the car?

The acceleration of the car is 1.25 m/s².

Explanation:

Given that,

Initial velocity = 15 m/s

Final velocity= 30 m/s

Time t = 12 sec

We need to calculate the acceleration of the car

Using equation of motion

Where, v = final velocity

u - initial velocity

t = time

Put the value in the equation

Hence, The acceleration of the car is 1.25 m/s².

the velocity you are looking for is made up of two parts: horizontally velocity, vh, and its vertical velocity, vv. the actual velocity of the ball will be these two parts added together, and because velocity is a vector then they will need to be added vectorially.  

neglecting air resistance etc etc.,  

the horizontal velocity component will be constant (because there is no accelerating force in the horizontal direction.  

vh = 8 ms-1  

the vertical velocity component has an accelerating force: 'g'.  

using v = u +at where a = g = 9.81 ms-2.  

the vertical component of velocity, vv = 0 + gt = vv =9.81 x 2  

vv = 19.62 ms-1 . the zero appears because the virtical component of velocity at time t=0 is zero. remember, the ball was thrown horizontally.  

how fast it will be moving (it actual path (being a parabola )) will be the vector sum of these two.  

adding vectorally gives: -  

v = sqr root (8^2 + 19.62^2) = sqr root(64+384.9) = 21.18 or 21.2 ms-1

i think the answer would be b