Can someone help me with 6 and 7
2 answers:
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Answer:
4.2 km
Explanation:
A triangle is a polygon with three sides and three angles. There are different types of triangles such as isosceles triangle, scalene triangle, equilateral triangle and right angled triangle.
Sine rule states that for a triangle with angles A,B and C and corresponding opposite sides a, b, and c, the following formula holds:
Let the starting point be A, hence the side opposite to the angle = a = distance travelled in north east direction.
Let the point of 60° of northeast be B = 90° + (90° - 60°) = 120°, hence the side opposite to the angle = b = resultant displacement = 8 km.
Let C be the endpoint, hence the side opposite to the angle = c = distance travelled north = 5 km
Using sine rule:
∠A + ∠B + ∠C = 180° (sum of angle in a triangle)
∠A + 120 + 32.8 = 180
∠A = 27.2°
Therefore she travelled 4.2 km in the north east direction
Answer:
2. The metal surface exerts less frictional force because there are fewer bumps and irregularities on it than there are on the concrete.
Explanation:
Frictional force is a force that is exerted between two surfaces in contact with each other. Frictional force always opposes the direction of relative motion of the two surfaces: for instance, for a ball moving along a surface, the force of friction exerted by the surface on the ball points opposite to the direction of motion of the ball.
The magnitude of the frictional force for a ball moving on a flat surface is given by
where
is the coefficient of friction
m is the mass of the ball
g is the acceleration of gravity
The value of depends on the type of surface involved. In particular, a smooth surface has a smaller value of
, while a rough surface will have a bigger value. In this case, we are comparing a smooth metal surface with concrete: since the metal surface has fewer bumps and irregularities than concrete, it has a smaller value of coefficient of friction, so it exerts less frictional force than concrete.