The third choice is correct
Answer:
The minimum stopping distance when the car is moving at
29.0 m/sec = 285.94 m
Explanation:
We know by equation of motion that,

Where, v= final velocity m/sec
u=initial velocity m/sec
a=Acceleration m/
s= Distance traveled before stop m
Case 1
u= 13 m/sec, v=0, s= 57.46 m, a=?

a = -1.47 m/
(a is negative since final velocity is less then initial velocity)
Case 2
u=29 m/sec, v=0, s= ?, a=-1.47 m/
(since same friction force is applied)

s = 285.94 m
Hence the minimum stopping distance when the car is moving at
29.0 m/sec = 285.94 m
According to Newton's second law of motion, the acceleration of a body is directly proportional to the force acting on the body and inversely proportional to its mass. The formula for this law is
F=ma
=4000kg * 2m/s 2 =8000N
Answer:
θ=142.9°
Explanation:
d=1 *r
angle ϕ= 37.1°
the line connecting pebble and target should be tangent to a circle so
cos(180-ϕ-θ)=
=
∴ θ=180-ϕ-
θ= 180-37.1-0
θ=142.9°
The question is incomplete. Here is the complete question.
A floating ice block is pushed through a displacement vector d = (15m)i - (12m)j along a straight embankment by rushing water, which exerts a force vector F = (210N)i - (150N)j on the block. How much work does the force do on the block during displacement?
Answer: W = 4950J
Explanation: <u>Work</u> (W), in physics, is done when a force acts on an object that has a displacement form a place to another:
W = F · d
As the formula shows, Work is a scalar product, i.e, it results in a number, so, Work only has magnitude.
Force and displacement for the ice block are in 2 dimensions, then work will be:
W = (210)i - (150)j · (15)i - (12)j
W = (210*15) + (150*12)
W = 3150 + 1800
W = 4950J
During the displacement, the ice block has a work of 4950J