Answer:
The work done by friction was 
Explanation:
Given that,
Mass of car = 1000 kg
Initial speed of car =108 km/h =30 m/s
When the car is stop by brakes.
Then, final speed of car will be zero.
We need to calculate the work done by friction
Using formula of work done



Put the value of m and v



Hence, The work done by friction was 
Answer:

Explanation:
First, denote our known values;

Mass is impulse divided by change in velocity:

Hence, the mass of the ball is 141.30grams
Answer:
send the wagon down a higher hill
Answer:
option D
Explanation:
given,
A conductor is carrying current = 2.0 A is 0.5 mm thick
Hall voltage = 4.5 x 10-6 V
uniform magnetic field = 1.2 T
density of the charge = n =?
hall voltage =


n = 6.67 × 10²⁷ charges/m
hence the correct answer is option D
Answer:
A) s = 796.38 m
B) t = 12.742 s
C) T = 25.484 s
Explanation:
A) First of all let's find the time it takes to get to maximum height using Newton's first equation of motion.
v = u + gt
u = 125 m/s
v = 0 m/s
g = 9.81 m/s²
Thus;
0 = 125 - 9.81(t)
g is negative because motion is against gravity. Thus;
9.81t = 125
t = 125/9.81
t = 12.742 s
Max height will be gotten from Newton's 2nd equation of motion;
s = ut + ½gt²
s = (125 × 12.742) + (½ × -9.81 × 12.742²)
s = 1592.75 - 796.37
s = 796.38 m
B) time to reach maximum height is;
t = u/g
t = 125/9.81
t = 12.742 s
C) Total time elapsed is;
T = 2u/g
T = 2 × 125/9.81
T = 25.484 s