A dog strapped to a trolley is accelerated uniformly from rest, so that after 10 seconds it has achieved a speed of 15 m.s-1. Find its acceleration.
a = 1.5ms-2
A mass of 5kg is in equilibrium, hanging by a light inextensible string. What is the tension in the string?
T = 49N
Name 3 locations that are included in the Large Data Set.
In the UK - Camborne, Heathrow, Hurn, Leeming and Leuchars.
Outside UK - Beijing, Jacksonville and Perth
What does H0 and H1 stand for?
H0 - Null Hypothesis
H1 - Alternate Hypothesis
What does mutually exclusive mean?
Outcomes that cannot happen at the same time.
A car is driving at 20 ms−120 ms−1. After 10 seconds, its speed is 50 ms−1.
How far does it travel in this time?
s = 350m
Two particles A and B have mass 0.4 kg and 0.3 kg respectively. The string passes over a small smooth pulley which is fixed above a horizontal floor. The particles are released from rest. Find the tension in the string immediately after the particles are released.
T = 3.36N
What is measured in 'oktas'?
Cloud cover
Define the critical region for a hypothesis test.
A set of values for the test statistic for which the null hypothesis is rejected.
What is the probability of getting a total of 11 when rolling 2 dice?
2/36 = 1/18
Danielle jumps from a diving board 10 m above a pool. If her initial velocity (upwards) is 1 ms−1, how long does it take her to reach the water?
Assume g=10 ms−2.
t=1.52 s (to 2 dp)
The mass of A and B are 4kg and 3 kg respectively. A sits on a smooth surface. The system is released from rest. What is the acceleration?
a = 4.2ms-2
Between which months are the readings for the LDS taken?
May to October
Given X ~ B(25, 0.3).
Find P(x < 4)
p(x<4) = P(x<3) = 0.0332
Are events G and C independent?
P(GnC) = 0.288
P(G) x P(C) = 84/160 x 87/160 = 0.285
So they are NOT independent
James, Jeremy and Richard are having a quarter-mile race. From rest, Richard accelerates at a constant rate of 8 mph/s. Jeremy sets off one second earlier than he should, and accelerates at 7 mph/s. James is given a 3 second head start on the other two, but his acceleration is only 5.5 mph/s. Who crosses the line first and in what time?
James: t = 18.09 s
Jeremy: t = 17.04 s
Richard: t = 18s
Richard crosses the line first
The mass of A and B are 4kg and 3 kg respectively. A sits on a smooth surface. the system is released from rest. What is the tension?
T = 16.8N
What years were the various bits of data taken in the Large Data Set? You need both years to get the mark.
1987 and 2015
Bob grows tomatoes. Over a period of time, he has found that there is a probability 0.3 of a ripe tomato having a diameter greater than 4 cm. He decides to try a new fertiliser. In a random sample of 40 ripe tomatoes, 18 have a diameter greater than 4 cm. Bob claims that the new fertiliser has increased the probability of a ripe tomato being greater than 4 cm in diameter. Test Bob's claim at the 5% level of significance. State your hypotheses clearly.
H0 : p = 0.3; H1 : p > 0.3
P(X ≥ 18) = 1 – P(X ≤ 17) = 0.0320 < 0.05
Evidence to Reject H0 or it is significant New fertiliser has increased the probability of a tomato being greater than 4cm
The random variable X has probability function
P(X = x) = kx, x = 1, 2, ..., 5.
Find P(X < 4)
k = 1/15
P(X < 4) = P(X = 5) = 5/15 = 1/3 = 0.333
A stone is projected vertically upwards from point O with a speed of 19.6 ms-1. Modelling the stone as a particle moving freely under gravity, find the length of time the stone is more than 14.7m above the O.
t = 2 seconds
Two particles P and Q have mass 0.5 kg and m kg respectively, where m < 0.5. The particles are connected by a light inextensible string which passes over a smooth, fixed pulley. Initially P is 3.15 m above horizontal ground. The particles are released from rest with the string taut and the hanging parts of the string vertical. After P has been descending for 1.5 s, it strikes the ground. Particle P reaches the ground before Q has reached the pulley. What is the value of m?
m = 0.278 kg = 5/18kg
Which UK location would have the coolest temperatures?
Leuchars as it's the furthest North and coastal.
A single observation x is to be taken from a Binomial distribution B(20, p).
H0 : p = 0.3
H1 : p ≠ 0.3
Using a 5% level of significance, find the critical region for this test. The probability of rejecting either tail should be as close as possible to 2.5%.
X ~ B(20, 0.3)
P (X ≤ 2) = 0.0355
P(X ≥ 11) = 1 – 0.9829 = 0.0171
Critical region is (X ≤ 2) ∪ (X ≥ 11)
The random variable X has probability function P(X=x ) = (2x-1)/36 x = 1,2,3,4,5,6.
Find P(2 < X < 5)
P(2 < X < 5) = 21/36 = 7/12 = 0.583