I don't think that 4m has anything to do with the problem.
anyway. here.
A___________________B_______C
where A is the point that the train was released.
B is where the wheel started to stick
C is where it stopped
From A to B, v=2.5m/s, it takes 2s to go A to B so t=2
AB= v*t = 2.5 * 2 = 5m
The train comes to a stop 7.7 m from the point at which it was released so AC=7.7m
then BC= AC-AB = 7.7-5 = 2.7m
now consider BC
v^2=u^2+2as
where u is initial speed, in this case is 2.5m/s
v is final speed, train stop at C so final speed=0, so v=0
a is acceleration
s is displacement, which is BC=2.7m
substitute all the number into equation, we have
0^2 = 2.5^2 + 2*a*2.7
0 = 6.25 + 5.4a
a = -6.25/5.4 = -1.157
so acceleration is -1.157m/(s^2)
Answer:
7 ms⁻¹
Explanation:
When the weight is 50% more, if the actual weight is W, the weight at the dip will be 1.5 Mg . At the bottom, the forces acting are
Weight Mg , vertically downwards
Centripetal force towards the center of the circle
and the normal force N = 1.5 Mg, that acts towards the center
N - Mg = Mv²÷ r
1.5 Mg - Mg = M v² ÷ r
0.5 g = v² ÷ 10
⇒ v = 7 ms⁻¹ Car's speed at the bottom of the dip.
The working equation for this one is:
E = F/Q, where E is the strength of the electric field, F is the electric force and Q is the charge. Substituting the corresponding values, the strength of the electric field is equal to
E = -30 nN/-3 nC
E = 10 nN/nC
The Atomic Theory changed during the last several hundred years because:
D. as new discoveries are made existing theories are revised or replaced.
Though there is a new atomic theory, the value of previous atomic theories does not diminish because these theories were the basis of the new theory drawn upon further studies made on studies conducted by the previous theories with the use of modern scientific method to produce more accurate and reliable result.