Danny kicks a ball at 5m/s at an angle of 20 degree above the horizontal and luke, who is standing north of danny, catches it. what direction is the ball's acceleration when it is at the apex ( top of its path ).
b) when the ball is halfway to the top of its path, what direction is its acceleration

you so much

Force=7.71KN in the opposite direction

Explanation:

Given the mass of the car(M)=1000Kg

The initial speed of the car(u)=100km/hr

we know that 1km/hr=5/18 m/sec

100km/hr=100*5/18 m/sec=27.77m/sec

the distance travelled before it stops (s)=50m

let the acceleration of the car be a

The final velocity of the car is 0.

we know that  

a=7.712m/

We know that F=Ma

F=1000* 7.712=7712N=7.71KN

be subject to a force andchange its motion

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)