Answer:

Explanation:
Time to mow 1 lawn by Wilma is 80 minutes
so work done in 1 minute by Wilma is given as
Similarly Rocky mow same lawn in 120 minute
so work done in 1 minute by Rocky is given as

now we know that they both worked by "t" time
so total work performed by them

they both mow 2 lawns then it is given as


Explanation:
Given that,
The initial velocity of a skater is, u = 5 m/s
She slows to a velocity of 2 m/s over a distance of 20 m.
We can find the acceleration of skater. It is equal to the rate of change of velocity. So, it can be calculated using third equation of motion as follows :

a = acceleration

So, her acceleration is
and she is deaccelerating. Also, her initial velocity is given i.e. 5 m/s.
Answer:
The magnitude of the electric field be 171.76 N/C so that the electron misses the plate.
Explanation:
As data is incomplete here, so by seeing the complete question from the search the data is
vx_0=1.1 x 10^6
ax=0 As acceleration is zero in the horizontal axis so
Equation of motion in horizontal direction is given as


Now for the vertical distance
vy_o=0
than the equation of motion becomes

Now using this acceleration the value of electric field is calculated as

Here a is calculated above, m is the mass of electron while q is the charge of electron, substituting values in the equation

So the magnitude of the electric field be 171.76 N/C so that the electron misses the plate.
Answer:
0.182 m/s
Explanation:
m1 = 30,000 kg, m2 = 110,000 kg, u1 = 0.85 m/s
let the velocity of loaded freight car is v
Use the conservation of momentum
m1 x u1 + m2 x 0 = (m1 + m2) x v
30,000 x 0.85 = (30,000 + 110,000) x v
v = 0.182 m/s