A 2.1 times 103 - kg car starts from rest at the top of a 5.0 - m - long driveway that is inclined at 20 deg with the horizontal
. If an average friction force of 4.0 times 103 N impedes the motion, find the speed of the car at the bottom of the driveway.
1 answer:
Answer:
speed of the car at the bottom of the driveway is 3.8 m/s
Explanation:
given data
mass = 2.1× 10³ kg
distance = 5 m
angle = 20 degree
average friction force = 4 × 10³ N
to find out
find the speed of the car at the bottom of the driveway
solution
we find acceleration a by force equation that is
force = mg×sin20 - friction force
ma = mg×sin20 - friction force
put here value
2100a = 2100 ( 9.8)×sin20 - 4000
a = 1.447 m/s²
so from motion of equation
v²-u² = 2as
here u is 0 by initial speed and v is velocity and a is acceleration and s is distance
v²-0 = 2(1.447)(5)
v = 3.8
speed of the car at the bottom of the driveway is 3.8 m/s
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Given :
Vector A has a magnitude of 63 units and points west, while vector B has the same magnitude and points due south.
To Find :
The magnitude and direction of
a) A + B .
b) A - B.
Solution :
Let , direction in north is given by +j and east is given by +i .
So , and
Now , A + B is given by :
Direction of A+B is 45° north of west .
Also , for A-B :
Direction of A-B is 45° south of west .
( When two vector of same magnitude which are perpendicular to each other are added or subtracted the resultant is always 45° from each of them)
Hence , this is the required solution .